Black Costume
To unlock Spider-Man's black costume in any console version of "Spider-Man 3," you must beat the game. Beating the game entails completing all 26 story missions, defeating the Sandman and triumphing in a final battle with Spider-Man villain Venom. Use Spider-Man's Super Attack combo to make the fight easier. Once you've beaten the game, you can play through it again in Spidey's black costume.
Peter Parker Costume
An unintentional glitch in the game allows gamers to ditch the colorful costume and play as Spider-Man's pedestrian alter-ego, Peter Parker. On the Daily Bugle mission, talk to Robbie inside the building. After Robbie gives you a mission, exit, re-enter and wait in the building for about seven minutes until the "Mission Failed" message appears. Select the "Do Something Else" option. This transports you to the top of the Daily Bugle wearing Peter Parker's street clothes rather than Spider-Man's outfit. From here, you can fall off the side of the building to run around the city as Peter Parker.
New Goblin Costume
In the Collector's Edition of "Spider-Man 3," you can wear an additional costume not available in other versions of the game. Beat the game just as you would to unlock the black suit and you'll find that you've also unlocked the option to play as the villain New Goblin, complete with his green costume, goggles and hover glider.
Other Costumes
Beating the game yields a few more costume choices than just the famous black suit. Once you've completed "Spider-Man 3," start a new game and go to the pause menu. Select "Upgrades." From here, you can choose to play as Venom, Sandman or the Lizard, complete with each character's film and comic-accurate costumes.