Fields of Fire is an online community for Vietnam wargamers. The site has a lively discussion forum, and focuses both on miniature wargames and on role playing games. Among the games supported are the classics Recon, from Palladium and RAFM’s Charlie Company, both of which I own and have enjoyed.
De Bellis Vietnam is a set of DBA-based quick and dirty rules for wargaming Vietnam.
Low Level Hell is a set of free wargames rules for helicopter actions in Vietnam.
Recon, The Role Playing Game Of The Vietnam War was published in 1982 by Role Playing Games, Inc.
Nam ’69 is a set of free wargames rules for company level rules in the Vietnam Conflict. In the game the players control American squads, while a referee controls the Communist forces.
Other game resources: