R.M.
I did a few things...I broke down and started visiting the chiro, it helped a lot with the pain I had with sleeping at night. I stopped going (and so did the pain) after the baby was born.
I also agree with the pool. I swam for 30-45 min 3-4 times a week up until about 2 weeks before my daughter was born.
And finally, I spent the last week-two weeks on the couch, it was the most comforable for me at that point.