Jailbreaking is stupidly simple. Now adding Flash to your iPhone is just about as easy. Benm.at, that site that used to add tethering to your iPhone, now has Frash in its repository. One you’ve jailbreakme‘d,
1. Open Cydia > Manage > Sources
2. Edit source and add http://repo.benm.at
3. Search Frash and install it.