Unfortunately .fm domain names don't sell to well. Fast.fm - $750 - 12/02/2006 Fashion.fm - $400 - 06/18/2007 Wines.fm - $170 - 12/30/2006 Probably would be better to develop that domain name than to try to sell it.
I think that this website could be worth a lot after development. Last.fm was bought for $280m by the way. The tld doesn't matter as much to search engines as the keywords and I believe it gets searched for a lot.