Cornell University's fellowship database (a comprehensive list of fellowships available)
Smithsonian Institution offers fellowships for research and study in a variety of fields. There are opportunities for senior fellowships, postdoctoral fellowships, predoctoral fellowships, and 10-week graduate student fellowships. All fellowships include a reasonable stipend. Additional information and application materials are available at http://www.smithsonianofi.com/.
Geology and Geophysics Fellowships - Fellowships carrying stipends from $500 to $6,000 are available to candidates for the M.S. or Ph.D. degrees with a major in geology or geophysics. For further information, contact the Department of Geology at (307) 766-3389.
Humboldt Research Fellowship enables highly-qualified scientists and scholars of all nationalities and all disciplines to carry out research projects for extended periods of time in cooperation with academic hosts at research institutions in Germany.
Mechanical Engineering Fellowship - Marinos Doctoral Fellowship in Fluid Mechanics: http://wwweng.uwyo.edu/mechanical/research/marinos.html