RiP Dev has released an updated version of Pusher that puts Installer.app on your 2.2.1 iPhone. The application 'pushes' tools onto the user partition of the phone without opening the system partition up!

In addition to newly released 2.2.1 firmware support, Pusher will work just as well for 2.0.2, 2.1 and 2.2 iPhones! However, we recommend you to stay on the bleeding edge and give 2.2 a try it represents many hours of hard work of Apple engineers.

Currently, the Pusher application is only available to Mac users; however, a Windows version is coming soon.

***If you have a 3G iPhone and are looking to keep your unlock in the future please don't update to 2.2.1 yet***