It's actually very easy:
1) Test your app in 3.0
2) Log your bugs
3) report OS bugs to Apple
4) Wait for the 3.0 version that fixes the bugs
5) Retest your app.
6) repeat as needed.
And in the mean time, while I'm waiting for Apple to fix *their* bugs, does my app sit in limbo waiting to be acceptedall the while I lose potential sales because my app doesn't work on beta software? I understand the need/want to make sure apps work with the new OS, but requiring apps to work with buggy software doesn't help anyone.