That's my pregnant belly at 32 weeks!
Once I was through my first trimester, I started taking prenatal yoga classes with a fantastic yogini - The Urban Poser. Every Monday night, I would drive to our local birth center and chiropractor's office for prenatal yoga. For the next hour and a half, I would relax. Stretching felt great, and the poses were modified to accommodate growing bellies. I was also taught different types of breathing and focusing techniques. Most helpful to me were the Birthing Breath, which helped me through contractions and deliver E quickly and safely. I can't recommend prenatal yoga enough to any moms-to-be. Just make sure that your instructor knows what she's doing as it is very easy for pregnant ladies to over stretch/overextend thanks to the hormone relaxin.
If you don't have a qualified instructor near you, check out these free podcasts from Mamaste Yoga.
Do you have a favorite form of exercise? When did you start?