I have been in the process of creating a cartridge database. The result of the initial efforts can be viewed at http://www.cartridgedb.com
The site include a simple search engine and a template driven result page with integrated voltage gain calculator and resonant frequency calculator (buttons appear if required data is present in cartridge's data record). There is also a resonant frequency "evaluator" page that takes your arm's effective mass and uses simple calculations to produce a table of expected resonant frequencies for a range of cartridges masses and dynamic compliance figures.
I have collected the data from a variety of sources. If you have any corrections or additions you would like to see, please contact me at firstname.lastname@example.org
The site has been tested with Internet Explorer 6 and Mozilla Firefox 1.0.1.