The fine folks at the Mayo Clinic have compiled a few easy exercises that will help prepare your muscles for labor. It's just like training for a marathon; the more toned your muscles become, the better they'll perform come the big day!
The excercises at the link range from simple kegels to the yoga-like "tailor sit." We particularly like the low back stretch, which looks like it feels great. Click here to see the whole range of exercises.