Flash Player uses a just-in-time compiler and virtual machine within a browser plug-in to play back content on websites. Those technologies are not allowed on the iPhone at this time, so a Flash Player for iPhone is not being made available today.

Flash Professional CS5 will enable developers to build applications for iPhone that are installed as native applications. Users will be able to access the apps after downloading them from Apple’s App Store and installing them on iPhone or iPod touch.

(from Adobe Labs)