I've the same problem with 3.0 on 3g.
Unfortunately, my iPod.app crashing wasn't as easily solved, though I agree it may have something to do with the improvements to Podcast playback. I just unchecked the Podcasts sync checkbox, and it didn't help, sigh.
If it's podcast-related, I'll try to fix the music playback, perhaps by completely reinstalling the 3.0 beta ipfw, then sticking to using RssPlayer.app for podcasts.
I just turned off music sync in iTunes, in the hopes that I can at least restore the iPod.app screen saying there's no content available, without fully resetting the iPhone. ( Wow sync is fast without the Music to slow it down
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)
And yes, now I've an iPod.app working again! It loaded on "Songs" where I last was, and oddly enough, it still has two copies of "Consolation Prize" by Julie Doiron, the free singe of the week that I downloaded once on my PC and once on the iPhone, in the hopes that clicking the "Purchased" button in iTunes.app on the phone would load iPod.app without crashing. (It didn't.)
Oddly enough, one of the two Consolation Prize songs is missing album art. Both are playable, however.
And there's no way to delete the songs, as you need iTunes to do that, and iTunes thinks there's no music on the device. Strange. Oh, actually iTunes sees just one of the two Consolation Prize songs, the one with album art. It's greyed out however, as Manually manage isn't checked.
Now, with Music still sync-disabled, I've re-enabled Podcast-sync to see if that works. (Copying over 10 GB of music takes longer.) I really do like how Podcasts now function, though I can't describe much here for fear of Apple's legal team. Suffice to say that if it works this summer, I see little need to keep RssPlayer, except when I want to download more than 10mb of podcast and not stream it.
And yes, Podcast sync finished, and iPod.app still launches. So it seems that if iPod.app crashes under the current 3.0 fw, you should be able to fix it by unchecking the Podcast sync, or the Music sync. If neither of those works, maybe try unchecking the Video sync also, though I didn't have to.
Hope this helps any other devs working with 3.0 on their everyday phone,
Louis.