This post was published more than a few years ago (on 2004-08-27) and may contain inaccurate technical information, outmoded thoughts, or cringe takes. Proceed at your own risk.
The Hitchhiker's Guide to the Galaxy is being continued on the BBC radio, starting in September, for the "Tertiary Phase" and in May of next year for the "Quadrenary Phase." Most of the old radio cast is back, and there's both a video and audio preview on the BBC's web page.