Just a heads up,
I was using Adsense in Real Estate Droid for about a month and a half. The app opens webviews at points, which displayed adsense ads along with the content. I was banned by Adsense last week, and my appeal was denied. Of course, they offer no explanation of why they banned me.
The explanations I can guess are:
1) T-Mobile traffic comes through a limited number of proxies, so it looks like only ~100 hosts are generating all that traffic instead of ~75000, so the traffic looks invalid.
2) They don't want Adsense for Content running on pages that are primary seen my mobile devices, even if those devices are fully capable of displaying the ads and rich web content. I had Adsense for Mobile on some pages, and Adsense for Content on others.
3) Someone thought it would be a good idea to help me out and clicked on my ads constantly. Or someone hates me and decided to click on the ads constantly to get me banned.
egyptianbman has already been banned by two other major non-mobile ad networks, and of course they don't give him any explanation either.
So if you're planning to monetize your app with ads, stick to the mobile ad networks. This kind of ruins me, because one of my apps had a very targeted, valuable demo, and all of the mobile ads are generally untargeted, but there's really no other option.
I do feel justified in pointing out the irony of Adsense disabling ads for an Android app. Like a snake biting its tail. It would be funny if it didn't reduce my income by $250/mo.