Pandora offers workout music stations specifically to get you pumped up about your workouts. Lists the Top 10 Pandora Stations for Workouts
Lauren Conrad's treadmill interval workout
This website is amazing for finding running/workout tunes!!! Runners: type in how long it takes you to run a mile, and it will give you a list of songs that will keep you on pace (it gives you the right number of beats per minute)... or enter the pace you want to run to give you a little boost. Love it!!