Captain Universe - complete the game on hard.

  Peter parker - in item collection find the hidden kraven room peter
  will be inside speak to him then you have his costume.

  Quick change spidey - get 10,000 pionts in zip-line training.
  Spidey 2099 - get all comics (when got them spidey says Golden.)

  

This isn't really a code but it is still pretty entertaining. at the
  cheats menu, type in your favorite cuss word and spidey will come and
  attack the word, turning it into some kind of nice word:

  PRETTY, FLUFFY, SODA POP, LOVE, NICE, SUGAR, BALLOON, CLOUD, HONEY,
  CAKE, DONUT, BUNNY, TAFFY and LOBSTER are some of the words i found...im
  sure there are more, but thats all i could see so far. Have fun, but
  dont get in trouble!!  =)

Enter   STICKYSTUF   as your code in the Cheat Code menu for unlimited webbing

When you get to the part in this level where you start climbing up the
  building while the Police Chopper is fireing at you there is a Captain
  America billboard.To get to see it you go to the part of the climbing
  where it says checkpoint.Once you get there just climb all the way to
  the right side of the building as you can go and just climb a little
  bit up and you will see it.

  

Select "Specials" at the main menu, then select "Cheats". Enter TURTLE as a code.

Select "Specials" at the main menu, then select "Cheats". Enter HELP ME as a code.