Open the C:\Documents and Settings\[login name]\Application Data\Gearbox Software\Earned In Blood\[profile name]\eib.ini file in Notepad.  Replace:

Consolekey=0

with:

Consolekey=192

Replace:

bEnableDebugConsoleAndMenu=False

with:

bEnableDebugConsoleAndMenu=True

Save the file, launch the game, and then press [~] during gameplay tp bring up the console and enter these cheats: