As I've said, they need to be careful how they do this. I'm still not convinced adding a Flash plug-in is a wise decision.
First up, it's a processor hog. Just playing back animated GIFs slows down iPhone's Safari browser some, can you imagine a complex Flash app running actionscript? Processor hog also equals battery hog.
Also, there's the issue of compatibility. There's no such thing as "hover" on the iPhone. Will some Flash apps not work? Let's not forget bandwidth. A lot of Flash is pretty small but others are not.
Also, consider this: If you embed audio into a web page, Safari will not automatically play the audio. Instead it puts a little play button in the upper left that you must tap which opens the audio clip in the built in Quicktime player. Now, why do you think they did this? The reason I think they did is because if sound played on Safari, it would play over the top of your music, or your phone call or both.
Now add a Flash plug-in which can ALSO make sound. How are they going to deal with that. Imagine visiting a web page with a fun Flash game and suddenly you get a phone call. That Flash game's sound and music better shut the hell up somehow.
Do I want Flash support on the iPhone? Yes, but only if they've considered all of these issues carefully. I think most people haven't considered any of these issues.