Vassar College
Vassar College: The Wars for Vietnam: The Documents
Document excerpts from the years 1954-1973 demonstrating U.S. support of South Vietnam. Includes links to other Vietnam sources.
The History Place
The History Place: The Vietnam War America Commits
This site from The History Place provides a lengthy timeline, accented with many quotations, explaining how America came to be directly involved in Vietnam. This is a great site to check out on the subject.