Council on International Educational Exchange (CIEE) has two scholarships for US students:
Bowman Travel Grant: for high school or undergraduate students participating in a CIEE program or program of a CIEE member institution. Award amounts range from $500-2,000. In most cases, awards are issued as vouchers to Council Travel, to be used towards the purchase of the student's airline ticket to their program destination. Application deadlines are usually in April and October.
The Bailey Scholarship is intended to promote increased participation in Council’s International Study Programs by members of groups which have traditionally been under-represented in study abroad, especially ethnic minority students. 888-COUNCIL
American Medical Student Association
American Medical Student Association website includes an excellent online guide to fundraising, "Creative Funding for International Health Electives" useful for all students.
Reference Service Press "Financial Aid for Study and Training Abroad and Financial Aid for Research and Creative Activities Abroad" (Reference Service Press). The RSP databases are also available online to America Online subscribers (keyword RSP), or through some university libraries.
University of Minnesota, International Study and Travel Center (ISTC), Scholarships Database
An excellent, free online database of scholarships. Search categories include study, research and internships as well as location and other variables.