Photography and Recording
Many shows require a photographer for their publicity material, and also to photograph the show itself for archival purposes. Video recordings, which can be transferred to DVD to sell as memorabilia or at a profit, are also quite popular. Audio-only recording services also exist, for soundtrack CDs and "radio play" formats.
The Cambridge Theatre Photography group is an excellent starting point. 
Claude Schneider - Cambridge-based alumni, professional photographer specialising in portraits/headshots, show/concert photography, publicity design, and much more. [www.ClaudeSchneider.com]
CantabPhotos - an online gallery showcasing the finest photographic talents of students and graduates of Cambridge University. Many shows have been covered by the site's members, and you can contact the site or a member if you're interested in some photography. [www.CantabPhotos.com]
David Hone - Cambridge-based photographer, happy to do dress rehearsal and performance photography for free. Can provide prints and a web-based gallery. [www.dhimages.co.uk]
Loren Miles - Member of University Staff, happy to do dress rehearsal and performance photography for free. Contact details on [www.lookup.cam.ac.uk University Lookup].
Redbox Productions - Some of their DVD work includes Return to the Forbidden Planet, Faust the Panto, A Midsummer Night's Dream, Macbeth, Sprung! 2007 and many more. [www.redbox.tv]