do a search on Google for Realistic Classical Samples or wave files
or do a search for Realistic soundfonts, it will give a lot of pages for free
classical sounding instruments in soundfont format.
here is a link that has some pretty good Soundfonts(get the voices)
http://www.papelmedia.de/sf2/sf2_uk_index.htm
Also check ebay! It is amazing how many sounds for next to nothing can be found on ebay. I have a cd with 6000 sounds, waves(have to go into Kontakt to make a lot of them the instruments but still...) Ebay is a cool place for samples.
Hope that helped! <img src="/ubbthreads/images/graemlins/delight.gif" alt="" />
I just upgraded to Sonar 3 hoping it helps me with my mixes.

yo