If you like Organizer, you can continue to use it and use CS3 for editing. I did that for awhile, but am using Bridge now.
I haven't tried yet to import all my old tags into Bridge. But
here is one person's solution.
If you try it, let me know if it works. I've been lazy about tagging recently, but I really shouldn't be.
BTW, if my version of Elements handled the latest ACR plug-in, I would probably be sticking with Organizer over bridge. There are some things I like better about Bridge, but overall I think Organizer was easier to use and more convenient for browsing.
Duffy