Harvard Extension School is Harvard's continuing education program, open to the public, to take classes at night. There is a post-bac program in premedical studies, which is what I did. It's a really fantastic, very affordable program that is taught at the same caliber and by the same professors as the undergraduate college, but it is more accessible to adults, people returning to school after years off, people who work full time (since most classes are held in the evening), and people who don't have $40,000 a year to drop on school. There's a website:
http://www.extension.harvard.edu/