Okay, it's in beta, but I am absolutely stunned with the quality of this little app - https://play.google.com/store/apps/d...S5haWRlLnVpIl0.
Been playing with it on the train to and from work on my tablet (keyboard's pretty much an essential, but honestly I'd buy one just for this if I didn't have one already) and it is stunning.
None of that setting up Eclipse, and the SDK, and a virtual Android device (or connecting your actual one via USB). Just install, run, develop, compile, test, repeat. Okay so it's no Visual Studio 2010, but for hobbyist development (or even larger projects if you want to do some work on the road) it's amazing.
Seems to be built by hobbyists/enthusiasts rather than a business, so hopefully it'll stay free.