This is a method I’ve tested and used on the iPhone and the iPod Touch, and, in theory, should work on the iPad.

The first thing you need to do is jailbreak your iPod Touch/iPhone. Instructions are available here:
[For Windows] [For Macintosh]

iPad jailbreaking is right around the corner as well, as you can see from this video:

Once you have successfully jailbroken, you should be able to access a new icon on your iDevice called ‘Cydia’.

Within Cydia, follow these instructions:
1. Press ‘Manage’ (bottom of page)
2. Press ‘Sources’ (middle of page)
3. Press ‘Edit’ (top bar)
4. Press ‘Add’ (top bar)
5. A dialog box asking for a URL will pop up. Enter ‘http://cydia.imodzone.net’
6. Press ‘Add Source’
7. Press ‘Search’ (bottom bar)
8. In the search bar (top) type ‘iMobileCinema’
9. Your first result should be ‘iMobileCinema’. Press it.
10. Press ‘Install’ (top right)
11. Press ‘Continue’. Install will proceed
12. Press ‘Return to Cydia’

If you visit any flash enabled site, it should work.