Just type in during gameplay:

allen		radiation suit 
andrewbenson	invulnerability 
charlesjacobi	no clipping 
davidbrus	god mode 
deanhyers	strength 
digitalcafe	all map 
joelkoenigs	bootspork and "eat chex" 
kimhyers	position on map 
marybregi	invisibility 
mikekoenigs	all ammo 
scottholman	all ammo and keys 
sherrill	additional map info 

Thanks to Revolution readers The Big Bad Marine and James M. McGuire!