Two of the best, Lumpy. Follow your nose and you'll find great maps. (Very different on each site.)

First one is 1st Battalion 69th Armor Map Room:

http://www.rjsmith.com/topo_map.html

The second one is Jim Henthorne's map site. Go to the bottom and click through to the maps.

http://www.nexus.net/~911gfx/vietnam.html

Both are terrific.

Bob