Here you will find websites offering (travel) writers communities where you can exchange advice, participate in forums, read and write articles, post your portfolios, and search databases for job opportunities. — Gregory Hubbs
Media Bistro is the main U.S. portal and forum for freelance travel writers who work for magazines. It is heavily skewed to New York City since that's the center of the publishing world, but it does list travel writing jobs in other locations. Basic access is free, while a premium membership allows access to pitching tips for specific publications and discounts on seminars.
WritersWeekly is a fine newsletter and website with information on both books and freelance writing work. The site offers a message board to talk about shady publishers, editors, and agents and one for people who are looking for interview subjects. The site has a good smattering of freelance writing job listings each week, including some for travel writing.