NetBSD was the first of The Three free BSDs and developed from 386BSD 0.1 code, released as version 0.8 in 19 Apr 1993. FreeBSD directly is another direct fork from 386BSD 0.1, while OpenBSD is a fork of NetBSD.
NetBSD's goal in life is to be ported to your toaster, and everything else too. If you have some obscure hardware somewhere, NetBSD probably runs on it, or theres someone trying to port it to it. The current version 20030922 has ports to a total of 53 different platforms with 17 different CPUs.