The console commands are pretty standard across all games with valve.
I'm assuming you just want the basics
god = Can't die
noclip = lets you fly through walls
notarget = disables enemys combat AI
impulse101 = HEV suit, weapons, and ammo
If you need a full list you can visit Gamewinners
[Edited by SnJester, 8/9/2010 11:27:18 PM]