Belly sleeping baby??
My little girl is 2 weeks old, and we laid her on her belly (in the frog/fetal position, knees and arms tucked underneath her) for a nap this evening, and she's never slept better! I literally had to wake her up to play with her for a few hours so she would sleep tonight. And even then, she wouldn't wake all the way up til I laid her flat on her back. Then she just got pissy. lol. Before we let her sleep for several hours on her belly (we used to only let her have sparse, short naps this way), she had no issues sleeping in her bouncer or carseat (yes, I know... shouldn't let her sleep in the carseat, but I put a thick blankie under her to cushion the buckles and stuff, and she slept better that way. She won't sleep flat.). But now... now she's in her bouncer because she only slept for about 45 minutes on her back. She's been in the bouncer for 30 minutes and she keeps stirring. She did *just* fine on her belly earlier for the 3.5 hours she slept.... would it be bad if I put her on her belly to sleep again after she gets up and eats some more? 
Comments
Both my kids slept better on their bellies. My son, a preemie, slept in his carseat until 2 months (age adjusted), then on me (in a recliner, secured w/ blankets and boppy) until 6months (age adjusted), then on belly in crib in our room. My daughter, full term, slept on me til 2 months, then on belly in cosleeper...where she is right now @ 5 months!
For sids prevention, back sleeping is best. But, there is also a whole list of other prevention tips (most of which you are probably doing already). As a mom, you have to make many important choices for your baby. This is just one, so gather as much information as you can. Then, do what you feel is best for your little one.