Actually, they are announced that they are working on it. Early stages of development
Adobe has embarrassed themselves several times with completely ignorant comments regarding the iPhone SDK. These announcements seem to be coming from marketing folk with no technical knowledge who glanced at the SDK docs briefly.
The SDK doesn't provide any way for developers to write plug-ins for Safari, so Adobe can't "provide" Flash for Safari.
Even worse for Adobe, the SDK terms specifically prohibit applications from interpreting or compiling code of any sort, so Flash is a non-starter.
The only way this could theoretically happen is if Apple relaxed these restrictions for Adobe. Apple has made no public comments to that effect; off-the-record, they've mocked the very idea. They have zero interest in it; it can hurt them in myriad ways.
There will be no Flash on iPhone. Just accept it and move one.