I can't wait to start teaching android phone app design! I just completed the CS4HS App Inventor MOOC, a 5 week online workshop "focused on helping teachers learn how to incorporate App Inventor in their curricula. Participants also have the option to earn CEUS or complete a follow-up project to receive graduate credits". Very impressive program that I'd highly recommend, taught by MIT staff, as well, Google hangout archive video of the App Inventor "inventors" themselves. The team is in the process of transitioning the whole application onto the "cloud", making it web-based. You can access this beta version here, which includes the Designer (your "scene" editor), the Blocks (where you program, using dragable code "blocks" similar to the Scratch approach), and the Emulator (your "phone" player) . There's even the capability to connect your actual smart phone via USB to your computer and download the app you've created. So far, I've learned how to create an app where you program touching an image to make a noise, how to create a canvas on your phone on which you can draw, and how to program a simple animated scoring game. App Inventor itself doesn't allow you to draw custom sprites, but does allow you to import images. I've found it very easy to take the sprites available from Scratch and upload them to App Inventor. Additionally, I've tested MS Paint and imported custom sprites created here, as well (you could also use GIMP for Mac users). I'm working on lesson plans now integrating Scratch and App Inventor. To get an idea of tools and project ideas, check out these resources:

Gallery
TookKit

Ohhhh - and by the way, I came up with a workaround for that Kodu "rollercoaster" project from the last post. I tried the Microsoft Kodu team's suggestions; all seemed to involve intricate programming that I doubted would translate well for teaching new users. So, playing around further, found that "paths", which you use to tell the character how to move (move + on path), don't require terrain (ground). So, when you open your new project, immediately delete the green patch that comes up, then go to "path" to program, add your character on top of that path, move + on path, and the "glass walls" feature will keep your character on the path, no matter how fast you change your character's setting to move (R click on character, "change settings", move the slider bars for the first 4 that appear). Now, I did find that if you make your path too steep, the character will get stuck, so assuming that means no upside down paths would work, either? But here's hoping we've put a bug in the Kodu team's ear to add this functionality?