Press to launch Cydia from your Springboard.
Press the Sections tab at the bottom of the screen.
Tap to choose System from the list of Sections.
Tap to choose My3G from the list of Packages.
Press the Install button at the top right of the screen.
Press the Confirm button to begin installation.
Once the installation has completed successfully click the large Restart Springboard button.
Notice the new My3G icon on your Springboard. Press it to the launch the application.
Press the Sign In button to log in with your RockID. If you do not have one then press the Create New RockID button.
Enter your name, email address, and desired password then press the Create New RockID button.
My3G will then open and let you know that you have a 9 day trial.
Note**: We had to open My3G a few times before it got the licensing information correct.
You can now press the Home button then open your contacts and select a contact that has FaceTime. Press the FaceTime button to directly initiate a FaceTime call over 3G.
Normally it would fail indicating that you must be on Wi-Fi. Now it works!
*Note: After your 9 day trial expires, My3G costs $3.99.