Endangered Language Fund
Provides grants for language preservation projects and archives the resulting knowledge. Includes information on current and past projects, newsletters, and links to other language preservation organizations.
Endangered languages awareness and preservation project from National Geographic. Contains an interactive map of endangered language "hotspots", and links to sites specific to several of these languages.
Living Tongues Institute
Organization dedicated to studying, preserving, and revitalizing endangered languages around the world. Site discusses their goals and current projects, including an online dictionary for Tuvan, and copies of published linguistics articles.