I came across as fantastic tool for figuring out which agents actually SELL fantasy and science fiction. You may or may not be acquainted with Locus Magaine. It is the leading publication for tracking News, Reviews, Resources, and Perspectives of Science Fiction, Fantasy, and Horror. I'm not sure what the percentage of sales that are reported in Locus but I understand that it is very high (even higher than Publisher's Marketplace).
So I found this great spreadsheet that tracks sales reported in Locus for the past several years.
http://members.optusnet.com.au/~mgoodin68/locus.htm
It is fascinating to look at the list and see the names of the people who are getting sales. I'm sure it misses some but this is a great resource. It does bring up sales that PM doesn't.
I am absolutely fanatical about making a list of agents who sell fantasy as opposed to just saying they'll look at it and knowing what they have sold. I believe that for a relationship this important, you need to go in with all the knowledge you can.
Anyway a Locus subscription isn't cheap, but if you can it's worth subscribing to in addition to Publisher's Marketplace. And the spreadsheet is free for download.
[This message has been edited by JeanneT (edited February 22, 2008).]