Here are the cheat codes to be entered in the "secured line" box (key [ENTER]) :

motherrussia summon a M80 tank mofo!
coolihaveanewcar summon a CIA armored van
coolimthepresident summon a US president (so useless! ;)
swatatyourorders summon a SWAT
ymca summon a US cop
greenjelly summon a UK cop
bringoutthedead summon an ambulance
duckhunt summon a flying duck
blackhawkdown summon a SA12 anti-aircraft missile
yeepeekaye MEGABLAST!
keyholemaster unlock god vision
fortknox add $1000
ineedalltechnos unlock all buildings
bigbrother unlock camera mode (the camera key? ask TNT supersceners!)

/Brian