A list of BBS's that I personally try to call and support on a regular basis.
A Vintage BBS list maintained by my friend Justin Scott. He does a great job of maintaining this list and you should really consider using it as your starting point if you're in to Vintage BBSing. While you're at it, check out his BBS "DJ's Place" (it's in the list).
The Telnet & Dial-Up BBS Guide is the largest regularly maintained Bulletin Board System (BBS) guide that lists both Telnet (Internet based) and Dial-Up (modem based) BBS systems.