That's awesome. I got my Pebble on Kickstarter, but I've been too busy with school and work to work on a project. SDK2 is just the pick-me-up I need, and I'm really interseted in lab hours too.
I just created a hello-world project on cloudpebble.net, but my initial build is failing:
../src/main.c:1:23: fatal error: pebble_os.h: No such file or directory
compilation terminated.
Waf: Leaving directory `/tmp/tmpIc8vSE/build'
Build failed