[RobAtticus]

I don't personally use tabs at the bottom in my apps, nor do I see it as a prevailing trend in apps. However, I can see why you'd want tabs on the bottom: it's closer to your thumb if you're holding the phone one-handed. This makes it easier to use the tabs, since you don't have to reach across the screen.

[veeti]

A new design pattern in Android 4.0 (and available via Google's compatibility library down to 1.6) is that you're supposed to be able to swipe between tabs, so in theory there is no advantage to having them at the bottom. (Tabs in Android have always been at the top.)