Though it's geared a little more towards students and backpackers, the extensive (and free) guide to travel in the countries of Thailand, Laos, Cambodia and Vietnam at Travelfish "dot org" is invaluable for all sorts of travellers to the region. Says the homepage: "Find Southern Thailand's best islands, go trekking out of Luang Prabang in Laos, explore Cambodia's Angkor Wat and savour the charm of Vietnam's capital, Hanoi."

In any case, you'll find regional overviews, a trip planner, a membership registry/login for the free detailed guides, firsthand travel features and, of course, the #1 strength of using the Internet as a guide: quickly and regularly updated information on guides and entries, as well as message boards with up-to-date commentary and miscellaneous chatter. If you're planning a southeast Asian trip, it's well worth your while to have a careful look over the boards here for useful information.

[image via travelfish]