An excerpt from the new iPhone OS 4 License says:
This updated iPhone Developer Program License Agreement in the iPhone 4.0 SDK specifically prohibit the development of apps using "an intermediary translation or compatibility layer or tool," which would include Adobe's Flash, Sun's Java, or Microsoft's Silverlight/Mono.
This news is a blow to Adobe, which has been working furiously to develop its Flash to iPhone cross compiler as the key new feature for Flash Professional in Creative Suite 5 (CS5). The upcoming CS5 would allow the Flash Professional application to export existing Flash content into a native iPhone application package that could be legitimately sold in the iTunes App Store because it was no longer Flash, and therefore no longer needed any sort of external runtime to play. The new iPhone 4.0 SDK license is now even more restrictive and effectively prohibit the new Adobe CS5's add-on.
Apple's New iPhone OS 4 License Blocks Flash [via]