NSF graduate fellowship - This fellowship lasts for three years, and gives you a little bit of travel money. You must be a senior in college or in your first year of graduate school.  Check here for more info: http://www.fastlane.nsf.gov/a10/A10Menu.htm The application is due in early November.

NDSEG Fellowship Program - National Defense Science and Engineering Graduate Fellowship. Due Jan. 19. Usually for first year students.

North Carolina State University has put together a list of fellowship links here.

Other Fellowships from Government Agencies   Courtesy of NSF.

Here is the mother lode of fellowship links. Courtesy of the National Academy of Sciences.

Here is another good source of fellowship links courtesy of the Oak Ridge Institute For Science and Education.

The NASA Graduate Student Researchers Program (GSRP)  awards  fellowships for graduate study leading to research-based masters or doctoral degrees in the fields of science, mathematics, and  engineering.

There are lots of fellowships available for minorities and women, and also I have seen several industrial fellowships posted on bulletin boards around campus.

The National Acadamies offers several fellowships for minorities and women, particularly there are:

Ford Foundation Predoctoral Fellowships for Minorities.

Ford Foundation Dissertation Fellowships For Minorities.

Professional Societies

There are also awards available from the following professional societies, all of which offer reduced membership fees for students.

The Materials Research Society gives awards for various categories and reasons. The graduate student awards require the student to be author or co-author of a paper being presented at an MRS meeting.

The American Institute of Chemical Engineers (AICHE) has some awards for students, although I haven't looked closely at eligibility requirements.

The American Chemical Society also has an award program. None of these awards are specifically for graduate students, but they do not exclude them. You have to be nominated for these awards.