Wikitravel.org is a new collaboratively developed world-wide-travel-guide. A wonderful use of wiki technology, inspired by Wikipedia.
Check out Itineraries such as One Month in Southeast Asia which is a great example of the strength of a wiki structure. Will be interesting to see if pages that start as copies of the CIA World Factbooks, such as the Gaza Strip, will evolve to include on-the-ground travel alerts.
Its content is available under a Creative Commons license, who blogged it. Its just getting started, so give them (you) a hand.
[tip 'o the hat to Adina]
this is a great use for a tool like a wiki.