A superb and succinct overview of the war. It is broken down into chapters. This is a great group of readings to introduce each lesson about the war. http://www.digitalhistory.uh.edu/database/subtitles.cfm?titleID=71
A great timeline that traces the roots of the war through its effects until the turn of the century: http://www.pbs.org/wgbh/amex/vietnam/timeline/index.html
A great list of major characters throughout the war, on all sides: http://www.pbs.org/wgbh/amex/vietnam/whos/index.html
Here is a great source that is chornologically organized with primary source documents. http://www.mtholyoke.edu/acad/intrel/vietnam.htm
Vassar offers a great selection of sources and a complete overview on their site. http://vietnam.vassar.edu/ So, no more Vassar bashing.
http://servercc.oakton.edu/~wittman/chronol.htm This is another timeline website that has photos, links and offers great insight with both the American perspective and the Vietnamese perspective.
Here's a sight worthy of the gladiator namesake. This one offers multiple biographies and descriptions of events during the war. The site also acts as a nexus becase it has so many other links. http://www.spartacus.schoolnet.co.uk/vietnam.html
For teachers that have the luxury to utilize interdisciplinary units or teachers who want to work on statistics with their students, this site is as welcoming as a cold glass of lemonade at a hot 4th of July cookout. http://www.vhfcn.org/stat.html
More photos and even a few audio links! http://www.ibiblio.org/vietnam/vnpic.html
This site has lesson plans for teachers and also another listing of more websites for students and teachers to check out. http://www.besthistorysites.net/USHistory_Vietnam.shtml#LP