Michael here. Trailer #2 is now available in gorgeous 480P, 720P, and 1080P exclusively on Yahoo!:http://movies.yahoo.com/movie/1809804784/video/16357477
Also check out http://www.avatarmovie.com/, which has been massively updated with new pics (including the above shot of Jake's avatar wearing some kind of ear piece), new music, and more.
UPDATE: TheFilmStage has 126 beautiful 1080P screencaps from Trailer 2.