Vietnam/Modern Era 20mm Miniatures Gaming HQ
Am planning on having a campaign where each player's squads build up from green to veterans, if they survive.
The rules, at least the ones I am planing on using, perhaps with some modification, are "Where's Charlie" which can be printed for free off of the internet. This features calling in air and artillery support, helicopter tranports, hidden VC movement and lots of other related things.
Note that 20mm is the same as 1/72 scale.
If you want to run a game, and prefer another rules set, here are some of the free rules sets that I know of to look at:
[Fire Force]
[Where's Charlie?] and [Vietnam Crossfire.]
Also, "Charlie Company" a popular Vietnam miniatures game by RAFM may be ordered from the hobby center.