Vengeance

Game Revolution
Contains cheats to allow power, weapons, mission selection, and instant kills, and Game Shark codes.
http://www.gamerevolution.com/oldsite/games/codes/sony/colony_vengeance.htm

GameFAQs
FAQ covering characters, controls, ships, weapons, tactics, and cheat codes.
http://www.gamefaqs.com/console/psx/game/196952.html

IGN Guides
Covers tactics, mission walkthrough, and cheat codes.
http://guides.ign.com/guides/2323/