While SlingPlayer and Skype are both incredible applications, the fact that they are limited to WiFi is a bummer for both developers and iPhone users. Developers – who spent much time developing these apps for the iPhone – certainly had not planned to be limited to WiFi. This limitation exists for a logical reason: AT&T doesn't want these apps to suck the 3G network dry. iPhone users, who are ready to dish out money for these apps, lose the true value of these apps: their mobility (WiFi's not everywhere…and if you're in a hot spot, might as well use your laptop).
Good news! There's a way to hack the iPhone in order to use SlingPlayer Mobile, Skype, and Fring's VoIP over 3G.
The following simple process essentially tricks your iPhone into believing you're using WiFi, even when you're not.
1. Jailbreak your iPhone You have no reason to be scared. Jailbreaking your device is easy, safe, and well worth it.
2. Launch Cydia from the SpringBoard
3. Go to "Manage"
4. Search "Tricker ThreeG"
5. Install the application.
6. Press "Confirm"
7. Use SlingPlayer, Skype, or Fring
That's it! You're free, no longer barred by AT&T's 3G greed.