Determining how many users are using iPad 1 versus iPad 2?
Does anyone know if there is a simple way to obtain these statistics. My understanding is that Apple doesn't store this data anywhere on an app by app basis, is that correct?
I'm hoping to find a better way to store it instead of just sending it to a database (if possible)...
Apple does not make per-app stats available. You can install your own metrics (or use a 3rd party — I used to use Flurry but didn't bother with my next app).
You can estimate based on iPad sales. Wikipedia says over 15M iPad 1 and about 25M iPad 2.
(Personally, unless you're doing something with a camera or GPU-intensive game, I don't think it matters much. There's no difference that affects my apps.)