I walk/jog for about half an hour. Usually ends up being around 3 miles per day plus my yoga on top of that. I usually do push ups and small weights to keep my arms tone though I've had to start doing pushups on my knees bc of back issues. It's a pain but anything to keep me and the baby healthy. :) My hips have a bad tendancy to fracture or crack so exercises that really hard on my hips are a no go. That's why I love the yoga so much. I can still get my stretching and workout in without putting too much pressure.
I have been doing prenatal yoga, you can find videos on YouTube. My favorite is Laura dutta ( I think thats her name) and when I get the chance I go swimming and do water arobics