From the net:



When Peter Parker first discovers he can climb up walls (while in citizen clothing), he tests it out by climbing up a building in an alley. During this scene, you can clearly see his clothes hanging out forwards, indicating that the scene was filmed with him crawling along a floor horizontally.



In the scene where Mary Jane is being mugged by four men, Spider-Man throws two of the men into two windows behind Mary Jane. Then the camera goes back to Spider-Man beating up the other two guys. When the camera goes back to Mary Jane the two windows are intact.



In the scene where Goblin blasts into Aunt May's bedroom to scare her, she is praying with her back to the wall/window that is blasted out. Yet her only injury is three small cuts on the right cheek of her face (which was away from the blast). Later in the hospital, the three small cuts have changed position.



When Peter is beating up the robber that killed his uncle, he smashes his head into both windows of double doors. When he smashes the glass, the same shot is used twice to show his head smashing the glass.



When Harry introduces Peter to his father, Norman, and they're talking on the steps, there's a redhead in a purple sweater that walks behind Norman probably 3 or 4 times.



As the balcony at the youth festival falls apart, Harry Osborne is whacked on the left side of his head by falling debris. However, during the scene following this, Harry has a bandage on the RIGHT side of his head.



In the school cafeteria after Peter saves MJ, he notices the fork that is stuck to his hand. If you look at the back of his hand, the spider bite is gone. In the next scene, it is back again.



When Peter is taking out the trash, and begins talking to MJ, as MJ walks toward him you can see her underwear sticking out above her pants. As the shots change, this underwear seems to appear and dissappear.



In the scene where Peter Parker is taking M.J.'s picture for the school paper, the spiders dissapear.



In every other version of Spiderman - comics, cartoons, films, games, etc., Spiderman gets his web from web cartridges, not his wrists. Also, if he could shoot web from his wrists, how is it that he can shoot through clothing without making a hole? [This is probably the only comic/film discrepancy I'm going to include, just to stop people sending it to me. No other differences though, please...]



After Spidey saves MJ for the first time, there's a stain on Harry's shirt while he's talking on his cell. Then it cuts to Peter, then back to Harry. When it comes back to Harry, there's no stain on Harry's shirt.



In the balcony scene, Peter is in the crowd taking pictures and at one point spots Harry and Mary Jane (MJ) together. MJ is holding a martini glass in her hand as she talks to Harry. In the rest of the scene she is holding a champagne glass.



When Peter is drawing up ideas for his costume the hand is that of comic artist Phil Jimenez, current artist of Wonder. Phil Jimenez is right handed and Tobey is left handed. In one of the cuts the pen is in Tobey's left hand but it shows him drawing with his right.



When Norman Osborn (Willem Dafoe) is preparing for the super soldier experiment, he is seen wearing a watch on his left hand. After he removes his shirt, the watch isn't there.



When Peter and MJ are talking outside the diner, MJ's trechcoat collar is first lying flat, then is tucked in, then is flat, happens several times when the shot goes back and forth from Peter to MJ.



In the scene when the Osborne is testing the performance enhancers on himself, his heart stops. His assistant comes in and begins to apply pressure to his heart and doesn't remove the arm restraints. The next shot is shown from further away and the arm restraints are removed.



When Peter and Osborne are talking, their distance from the balloons changes.



Peter is supposed to help his uncle paint the kitchen - when Peter leaves the house the kitchen is green, when he comes back his uncle has painted it blue. The following scene the kitchen is green again.



Throughout the movie references to how long Spiderman has known Kirsten Dunst are made. It seems to change anywhere from six years old to sixth grade.



After Spider-Man saves MJ after the World Unity Festival and is swinging quickly away, he is carrying her so that she is facing backwards. When we see a shot of MJ smiling, however, her hair is blowing very lightly in the direction they're heading.



In the final battle scene, Goblin's costume alternates between clean (green) and dirty (white/dusty) throughout the scene.



In the graduation day scene as Norman Osbourne is talking with Peter Parker, Norman's right hand is on Parker's left shoulder then off. This happens a few times as the camera angle switches.



In the last scene where Spider Man beats up the Green Goblin, Spider Man is right next to him smashing him in the face. When Norman Osborn reveals himself as the Green Goblin, however, the camera is shot at a different angle and Spider Man is instantly a yard or so away from him.



After Peter picks up his 'winnings' from the wrestling promoter, we see the sillouette of the robber using his right hand (holding the gun) to hit the promoter on the left side of the head. After the robber escapes and the promoter askes Peter why he didn't stop him, the promoter is injured on the right side of the head.



In the wrestling scene the cage is lowered around the ring for the match. The announcer instructs the assistants to lock the 'doors' of the cage. In fact there are no doors. We see the assistants chaining and locking the 'corners' of the cage. Then at the end of the match when 'Spiderman' has won, the cage is immediately lifted away from the ring and there are no locked chains on the corners.



In the lunch scene, everyone notices Peter dragging the lunch tray. This seems like something noticeable to a point that they would say something when the Daily Bugle is asking who Spiderman is. Something that's not easily forgotten.



This is not a mistake, only a cameo appearance. Jameson (the boss at the newspaper) has the male assisstant who is dressed completely in black and has the glasses. This is in fact the director's brother, Ted Raimi.



In the scene where Peter is following M.J. to the bus stop (the morning after he was bitten), while Peter is talking to her we see the bus start to pull up behind him. Moments later one of M.J.'s friends pulls up in a green Mustang. The scene cuts back to Peter, and we see the bus pass by him again. Don't you think the bus would've passed the Mustang?



How did the referee get back into the cage during the match so quickly when the cage was still just rising?



In the appartment fire scene, Spiderman enters the building twice. In between time the fire backdrafts (explodes) out the building several times from different windows before and after Spiderman enters. Backdrafts only happen once, then the fire escalates rapidly never returning to a more passive state without intervention.



In the bridge scene, the orientation of the elements of the scene gets very confusing. There are so many camera angles that understanding where everything is becomes difficult. Nevertheless, it is very apparent that when Spiderman runs to dive off the bridge (to save MJ and the cable car), he jumps off the wrong side of the bridge.



When Spiderman returns to Peter and Harry's appartment (for Thanksgiving dinner after the firey appartment fight with Goblin), the slashing injury to his arm changes positions (from the apartment to the ceiling of his room to the dinner table).



At the bridge scene, MJ begins to climb down the steel cable, then the Green Goblin swoops in, attacks Spider-man and causes her to fall a considerable distance, yet she manages to catch on to the rail on the cable car. Now unless MJ has super powers of her own, cathing on to a rail after falling from that distance would be nearly impossible. Her arms would be yanked right out of the socket.



More at http://www.movie-mistakes.com/film.php?filmid=2225