Try Rhapsody for 14 days Free
Get unlimited access to music downloads. Free 14-day trial.
real.com

Napster Official Site - Get a Free 14-day Trial
Napster is the premier on-demand digital music download service. Try it for 14 days free.
napster.com

Download Music - Musicmatch On Demand
Play any song you want, however you want, from any PC. Now get a free 7-day trial.
musicmatch.com