You’re not alone – I’m right there with you. I just got CS3, and I’ll be diving head first into Flash (and ActionScript 3.0) in the next few weeks. I know there have been major changes, and it does seem intimidating. My copy of CS3 came with a DVD full of training videos, and Adobe is usually quite good at providing articles, tutorials, etc., for its developers. Their help documentation is helpful, too. I’m going to start with all of those resources and see how far I get…

Good luck! Let me know if you uncover any major “gotchas” – and I’ll do the same.