|MadSci Network: Astronomy|
There are a lot of schools with undergraduate majors in astronomy, but it's not necessary to major in astronomy if you want to be a researcher in astronomy. Many people major in physics as undergrads before going to astronomy graduate school. See this Careers in Astronomy, a brochure from the American Astronomical Society, for more info on astronomy careers.
With that in mind, if you want to be an astronomer it's probably a good idea to go to college which has astronomers, so you can find out what astronomy research is like. Not all places have separate astronomy departments; sometimes astronomers are in the physics or mathematics departments. Here are lists of astronomy departments worldwide: http://www.cv.nrao.edu/fits/www/yp_dept.html (including my alma mater, the University of British Columbia). Both lists look pretty complete to me, but if there's a particular college you're interested in you should check that college's webpage directly - the Yahoo list is a good place to start.
Good luck in your search for a college!
Try the links in the MadSci Library for more information on Astronomy.