General Travel

Lonely Planet - Offers travel advice, detailed maps, travel news, popular message boards and health information.
Frommers - Frommers.com brings you cheap airfares, bargain rate cruises, discounted hotel rooms, budget car rentals.

Air Travel

Frontier Airlines - Fontier Airlines information and schedule.
Japan airlines - Japan airlines flight schedule.

Preparation

Vietnam visa - The most comprehensive guide to Vietnam visa.
Vietnam tourism - The official site of Vietnam Tourism boards.
Been There: Vietnam - Collections of tips for the main destinations submitted by regular travellers.
Frommers.com: Vietnam - Information for visitors: planning, health, safety, accommodation, dining and attractions.
National Geographic: Vietnam - Vietnam facts, information and history, travel videos, flags, photos from National Geographic.
Vietnam Travel Watch - Travel warnings and safety notices for travelers to Vietnam.
Wikitravel: Vietnam - Constantly updated guide covering transport, food and drink, safety and attractions.
Wikivisa: Vietnam - An open source for Vietnam visa and passport information.
Vietnam - Vietnam travel and tourism guide with information on food and drink, safety and attractions.
Word Travels - Vietnam - Basic guide featuring an overview and description of some locations.
Travel Vietnam - All the information that you need in planning your vacation to Vietnam!.
World66.com: Vietnam - Complete, objective information on Vietnam travel, including photos and reviews.