Google music search

http://www.google.com/musicsearch

e.g.

Google music search on Jane Siberry

via Darren Barefoot - Google Music: Because Maps, Web Stats and Email Aren’t Enough

some info to be found in Google blog - Searching for music

Unfortunately it only exists for google.com, not google.ca, and it will cheerfully point you to US online music stores.  On the plus side, the iTunes links seem to work ok, I land at the correct item in the Canadian store if it exists, or it says "the item you've requested is not currently available in the Canadian store".