The easiest route to migrate up is to start a new project with a new scaffold and then add your Game code and resources to that. That way, the Sparrow start-up code will be correct, and that's the part where the biggest changes occur.
After that, you have to change some smaller things, e.g. the main game class now inherits from SPSprite instead of SPStage; and tweens now have block-callbacks instead of events. But all of that shouldn't be too critical.
Be sure to read over this FAQ, it lists the most important stumbling stones.
And one last thing: be sure to use the latest head revision! Or wait until next week, when Sparrow 2.1 is published.
If you need any more help, just post on. 🙂