Hi Jen. I know a similar question about this was posted not too long ago, but I couldn't find it on the first page here. You may want to look at page 2 or 3 and see if it's already made it that far.
I started working out, after giving birth to my second, about 2 weeks after delivery. I eased back into it using Cathe's newest series which back then, was Cross Train Express. I was on a 6" board, and modified or stopped if it was too much. I do know that my bleeding, which was pretty much gone already, did come back. I can't remember if I worked out 5 or 6 days per week, or if it was more like 3-4. I know my husband and I also took several 4 mile walks with her and my older son in the jogger stroller. I did not do situps for quite awhile afterwards as I've always read that the muscles stretch out and it can cause problems if they are not fully healed.
The main thing is to be sure to listen to your body, don't overdo it, and make sure you're getting plenty of rest.
Congratulations on the birth of your new baby!
Stacey