Marvel vs. Capcom 2 Cheats

Choose Juggernaut, Iron Man, and BB Hood (in that order). Put them all on their recommended assist types. Get 3 Hyper Combo bars and link them all together (L=R). It should kill the opponent in one hit. This move was tested on Cable, a medium damage taker.
Choose Juggernaut, Incredible Hulk, and Zangeif. When at level 3, let Juggernaut be your active character, get very close, and press L + R to make them all do their hyper combos. This will instantly kill your opponent's character. Note: This attack best works when your opponent is in a corner.

The order of your fighters will appear before a versus match, with "1", "2", or "3". You can select the first and second fighters of your team, and thus change the entire team order.
To select the first fighter, press LP + LK for the character marked "1", MP + MK for the character marked ''2'', or HP + HK for the character marked ''3''. Then, press the same button combos to select the second fighter. Press Start to continue.

Unlock all hidden characters and all extra costumes to be able to choose the same character 3 times on your team.

Note: This trick only works in training mode. Set the combo gauge to infinity in the training menu. Then, start a super and start another one. This can be done an unlimited amount of times. This works best with characters who have beam supers.