For now, this list is skewed a bit toward North America and the UK since that's where the sites with the most visitors tend to be. Please send suggestions for international sites to include to the moderator! - Tim Leffel
GuidebookWriters.com is a UK-based site offering promotion services and sharing of tips and info among guidebook writers. www.guidebookwriters.com.
TravelWriters.com is mostly a site set up to sell various services to travel writers and travel PR people. Gets mixed reviews on whether the fees pay off, but plenty of resources for those who can justify the investment. main.travelwriters.com/index.asp.
TravelWriter Market Letter is a monthly newsletter that provides writing guidelines, news from the travel publishing world, and press trip listings. Annual subscription required. www.travelwriterml.com.