TIES (The International Ecotourism Society) Perhaps the biggest name in ecotourism advocacy around the world is Washington, DC-based TIES, The International Ecotourism Society, which maintains the appropriately named domain www.ecotourism.org. TIES is a leading source for education, information and advocacy on sustainable travel, and the dynamic website boasts blogs and featured trips.
Sustainable Travel International
Another nonprofit advocacy group is Sustainable Travel International, which is dedicated to providing education and outreach services that "help travelers, travel providers and destinations support environmental conservation and protect cultural heritage while promoting cross-cultural understanding and economic development."
Transitions Abroad isn't the prettiest website, or the most user friendly, but it is a portal for ecotourism. The site is a repository of useful links on responsible operators and articles.
The venerable environmental group has done extensive work to green up travel, as well as to protect the planet's vanishing destinations.
Ecoclub is a network for practitioners and participants of ecotourism around the world to come together and share their experiences, through member profiles, blogs, articles and other means. The site hosts news and boards for jobs, grants, events and more.
Planeta, "the global journal of practical ecotourism," was founded in 1994. Although Planeta's design looks like it hasn't been updated since, it can be a useful resource for finding responsible travel options, as well as news and event info. The world directory of ecotours is particularly helpful.
Perhaps testifying to how mainstream ecotourism is becoming, major travel site Orbitz has its own hub for the sector. Get easy access to green hotels, news and much more.