We've known how this Cupcake tastes for a few days now, and we're still most excited about the soft keypad, of course, which will come in handy in the many situations where you don't want to flip open the G1 just to type a few letters. There are also a few mysterious new apps, some of which look like dev tools but may be polished for eventual release, as well as hints of haptic feedback for the keyboard and a few more tidbits. Check out our captioned gallery for a tour:
My number one wish, though, would have to be improved battery life via smarter data connection management. The G1's hardware battery may be partly to blame, but one of the reasons the G1 usually can't make it through a whole day without re-juicing is that the data connection is constantly active for email and contacts sync as well as push updates and whatever else you may be doing. Sure you can turn most of the automatic data syncs off, but that kind of defeats the purpose of the phone. Hopefully cupcake will fix some of this.
If you want to load Cupcake on your computer via the Android SDK, grab the SDK here. Then, follow the instructions laid out by the folks at Nullwire (very easy) to replace your system image files with the new 1.5 Cupcake versions, then simply run the "emulator" app (a UNIX executable on OS X and Linux, and an .exe in Windows) inside the SDK's "tools" directory and you're in business. [Nullwire]