The current release of OpenBSD is 2.5 which started shipping May 19, 1999. The CDs (and Shirts) can be ordered... OpenBSD is freely available from our FTP sites, and also available in an inexpensive 2-CD set. The costs of producing the CD sets have been underwritten by a grant from the USENIX Association.
For each release to become available on CD, project funding is still a big issue since OpenBSD has no real financial backer -- the development members team are volunteers. Every sold CD or financial donation makes it easier for us to make new releases.