I too have a workout from iAmplify that is really good. It's the Indoor Cylcing 101 from http://store.iamplify.com/index.php?...93b183f4f9d21b

Another good pay-as-you-go service is at itrain. Check out http://store.iamplify.com/index.php?...93b183f4f9d21b and click on iCycle.

Then there is always PodRunner.com that has music at a specified speed so can keep a steady cadence. They also have tracks that have "intervals" at a faster speed.

I've been using these three tools for a few weeks now to get in shape for the spring. It's been much more fun than just spinning along with no purpose.