I second what everyone else has said. I agree that yoga is a great compliment to cycling and just about any other sport. I picked up a book called Bike for Life a couple months ago and would note that it recommends yoga to essentially "undo" some of the stresses that cycling puts on your body. Cycling aside, yoga is a great compliment to life in general. It's benefits go so far beyond the physical. I can't sing its praises enough.

I do recommend that you read up on the various types of yoga to determine which one seems best for you and then see what the studios/gyms in your area offer. I tend to like rather fast-paced vinyasa (or flow) classes. I otherwise get a little bored. Wherever you go, I would also recommend that you try various instructors. You'll find that you like some and not others.