0. Make sure your iPad is jailbroken. It’s pretty easy — just follow the guide about how to jailbreak iPad with Spirit here.
1. Download Frash.deb and keep it nearby.
2. Decide how you’re going to get files onto your iPad. For Mac users, it’s dead simple — just install Netatalk, which will automatically pop up your iPad in the Finder’s Sharing list. Windows users can try out this guide at iClarified to get OpenSSH installed and running and use WinSCP — it’s just as easy. Either way, the login is “root” and the password is “alpine.” Remember, you can seriously screw things up while you’re in there, so be careful!
3. Once you’ve got access to the iPad’s filesystem, navigate to /var/root/Media as shown here:

4. Once there, open Media and create a folder called “Cydia.”
5. Open the new Cydia folder and create another new folder called “AutoInstall”
6. Upload Frash to your new folder.
7. Restart your iPad a couple times.
8. You’re set! Now just navigate to a page in Safari with non-video Flash content and hit the F logo to play it. Again, no video for now, but games and other simple content works. We did have a few crashes here and there, but it’s early code, and things are bound to get better.