According to Boardgame Geek, there's a good few boardgames covering the area, from Indochina war to Vietnam war, and beyond. See the listing, HERE.
Yes, I only just received my second boardgames, John Prado's Khe Sanh 1968, from Against the Odds magazine. Interesting articles on the magazine, too:

Previously, I only had the Dien Bien Phu 1954 game from Vae Victis magazine, in French even, but it was easy to find translated rules, a good set was available at Grognard.com for example.

Image from Boardgame Geek
So which Vietnam games do you guys own and play? Always interested to hear what's out there, and how do you like them [:)]