If you wish to do the detection yourself you might also like to take a look at the quick reference at diveintohtml5.com.
Now that Apple is foregoing Flash and championing HTML5, I believe the latter will take on even more significance for mobile. This doesn’t change the fact that I (and others) think that Apple might have made a mistake. No Flash on the iPhone is understandable. No Flash on a ‘full’ screen device such as the iPad is likely to disappoint end users.
Also, it’s far too easy now for Android, Symbian, Windows Mobile, Palm or any other OS to include Flash in a tablet and to try to improve on the iPad experience.