You probably know about this site already, but just in case, I found a great website at allmusic.com . I've found the Amazon search engine for classical music recordings kind of hit or miss, but the one at allmusic is good (at least I think it is, for recent recordings at least). It also has some background information and sound clips. Just use the regular search with composer and piece, set for classical music. I haven't figured out how to use the advanced search feature yet.