Since you've never done any at all, you may want to find a class for beginners. In the beginning, almost any form of yoga should help with your balance and controlled breathing.
I'm kind of in that boat myself, trying to improve my flexibility for TTs. I found a couple DVDs, Yoga for Inflexible People and Yoga for Cyclists that I'm working on (just for about 10 days now). It's not the same as going to a class, but for now it's fitting into my schedule better and getting me started.