There is a vast array of websites and other sources relating to the history of the Vietnam War; and not surprisingly, a large proportion of them are heavily biased in favour of the United States. Among other things, there is a widespread tendency to deny or obscure the extent, consequences and criminal nature of the U.S. war of aggression.
Sometimes the distortions are blatant, as with the plethora of websites devoted to glorifying the U.S. aggression. Many of these are maintained by veterans of the invading forces, in various efforts to exalt and justify their participation in perhaps the most unjustifiable war of the 20th century.
Other deceptions are more subtle, such as the diluted version of history presented on the website of the BBC News Service (often referred to as "reliable… highly respected", etc.). Even some of the sources cited below include elements that must be interpreted with caution.

It is therefore advisable to be familiar with the contents of The Pentagon Papers — the official U.S. history that provides an effective antidote to the most common myths, falsehoods and misleading perspectives. In addition to the complete text of the Gravel edition cited below, a concise summary of The Pentagon Papers is available in a PDF document (132 KB) on this website.

Another source of bias is the comparative silence of the principal victims. For a variety of reasons, Vietnamese, Cambodian and Laotian voices are seldom heard in the public discussion of the war and its consequences. (This does not apply to adherents of defeated puppet regimes who, from exile in the United States and elsewhere, hurl bitter lamentations and accusations at the current governments of their native lands.) Some references to the limited Vietnamese testimony that does exist are included in a report on this website; see also After Sorrow: An American among the Vietnamese.

Suggestions for additions to the following list are welcome and may be submitted via e-mail to:

Selected Web Resources on the Vietnam War
One of the world's foremost authorities on U.S. foreign policy, Noam Chomsky has written extensively on the Vietnam War and related subjects. Searching this website with the word “Vietnam” will yield numerous references.
Gravel, Senator Mike, ed.
The Pentagon Papers
Unique, indispensable history of the origins and early stages of the war. Self-incriminating U.S. government document, not intended to be made public.
Harvard Film Archive
At Home and Abroad: The Vietnam War on Film

Collection of "non-fiction and experimental works which documented the unpopular escalation of American intervention as well as the growing protest movement." (See especially "Hearts and Minds", currently available in DVD version.)
King, Martin Luther, Jr.
"Beyond Vietnam: A Time to Break Silence"
Devastating critique of U.S. war against Vietnam and its broader implications by the spiritual leader of the civil rights movement; delivered at New York's Riverside Church in 1967.

Moise, Edwin E.
Vietnam War Bibliography
Partly annotated list of references from a wide variety of sources, some more reliable than others.    
Mount Holyoke College
Documents Relating to American Foreign Policy: Vietnam
Collection of official and other documents covering period from World War I1 to the present.
National Geographic Society
Another Vietnam
Series of images captured during the war by Vietnamese photographers.
National Security Archive
Extensive collection of official U.S. documents and related information. Search website with the word “Vietnam”.
Public Broadcasting Service
Battlefield Vietnam
Comparatively even-handed treatment of the war and its aftermath. Especially useful for the personal testimony of participants on all sides of the conflict.
Schafer, John C.
Vietnamese Perspectives on the War in Vietnam
An annotated bibliography of writings by Vietnamese authors.
Shah, Anup
Media, Propaganda and Vietnam
Well-documented treatment of the stated subject, with numerous links and cross-references.

Spartacus Educational
The Vietnam War
Teachers and students comprise the principal target audience of this history website based in England.
Vietnam Veterans against the War
Organization founded in 1967 by U.S. veterans of Vietnam War whose purpose is to spread knowledge of "the ugly truth about U.S. involvement in Southeast Asia".
Winter Soldier Investigation
Transcript of 1971 conference based on eyewitness accounts of widespread criminal acts committed by U.S. troops against the citizens of Vietnam.
Note: These web links are valid as of July 2013. If a reference turns out to be inaccessible for any reason, try searching from the website's home page. In the case of Public Broadcasting Service, for example, shorten to merely The web address (URL) is usually displayed at the top of the web-browser; if it is not visible, the appropriate preference setting needs to be activated.