Unlimited stamina:
Press R(2), B, R(2), B at the main menu.

Indestructible weapons:
Press L, R, L, R, C-Left(2) at the main menu.

Big women wrestlers:
Press R(2), B(2), L(2) at the main menu.

Small wrestlers:
Press R(2), L(2), C-Left, C-Right at the main menu.

Alternate grunts:
Press R, L, R, L, B(2) at the main menu. The normal grunts will be replaced with rude sounds.

All hidden wrestlers:
Press C-Left(2), C-Right(3) at the main menu.

Alternate costumes:
To unlock any wrestlers hidden costume(s), win the Hardcore Challenge under any difficulty setting with that character.

Media Center for game play:
Win the game in Hardcore Challenge mode and get the Hardcore belt. Then, play for the U.S. Title. The Media Center will be unlocked before you complete it. Go to it and complete it for use in exhibition mode.

Parking Garage for game play:
Win both the Hardcore and U.S. Titles and go the World Heavyweight. The Parking Garage will be unlocked before you complete it. Go to it and complete it for use in Exhibition mode.

Extra creation mode attribute points:
Win the United States Heavyweight Belt as Jeff Jarrett to get two extra attribute points or win the WCW World Heavyweight Title as any character to get three extra attribute points.

lets see about this eh?

Thanks for this, I checked these out myself and they do work.

They work, they work! They actually work!