I went Harvard Extension and thought it was great. It has a good reputation and is very affordable (prices are online, but it's costs about the same as a city university). Amazing chem instructors that make OChem manageable. Downside is that it's night classes only (that can be a plus if you want to volunteer or work PT in the day).
If you're part of the HCP program and maintain your grades, you can get a committee letter. I don't know what the letter said, but **shug**, I'm in med school.
EDIT: BTW, There is a postbac forum on these boards. You can learn about various programs in boston there.