Enter this code at the main menu screen. You should hear a sound if entered correctly

Unlock Everything: 
Hold in the L trigger and press A, X, Y, B, A, X, Y, B 

Create A Character With These Names To Get These Effects: 
mstapley - Another Toon Backgraounds (Xbox Only) 
tpiperi - Big Feet 
okendall - Big Hands 
tho - Big Hands, Big Feet, Big Heads 
rtaylor - Big Heads 
edma - First Person Camera 
pjefferies - Ghost 
ksimeonov - Grey Scale 
jgintu - Halo 
mbilodeau - Toon Backgraounds (Xbox Only) 
pstapley - Toon Character (Xbox Only) 
ewilliams - Wire Frame 


To Unlock the Following Characters all you need to do is complete these stages(You do not have to complete the Talk Show Mode to get these characters).

All Other Characters: 
To Get All The Other Characters Just Complete Talk Show Mode With Any Of The Starting Characters. 

Dameon Redd: 
Go Through Talk Show Mode with JCW's Evil Dead and beat him in the Slaughter House Stage. 

El Drunko: 
Go Through Talk Show Mode with Karnage and beat him in the 
TruckStop Stage. 

Madrox: 
Go Through Talk Show Mode with Sabu and beat him in the Gentleman's Club Stage. 

Masked Horn Dog: 
Go Through Talk Show Mode with Masked Mike and beat him in the Backyard Stage. 

Movies: 
To Get The Movies Just Complete All The Extra Goals. 

Sally: 
Go Through Talk Show Mode with Violent J and Beat her in the Mansion Stage. 

Stages: 
Just Complete Each Stage To Unlock Them. 

Tom Dub: 
Go Through Talk Show Mode with Mad Man Pondo and beat him in the Talk Show Stage. 

Tylene Buck: 
Go Through Talk Show Mode with Shaggy 2Dope and beat her in the Shopping Mall Stage.