Honeycomb adds the equivalent of the "up" button you're describing here. The convention is that in the upper left corner of a screen there's a button that takes

Honeycomb adds the equivalent of the "up" button you're describing here. The convention is that in the upper left corner of a screen there's a button that takes you to your "home within the app" (e.g. the inbox for Gmail). I expect that this will filter into phone UIs with Ice Cream Sandwich.