Here's how to sideload iOS apps to iPhone or iPad on Windows or Mac using the Cydia Impactor tool. No jailbreak is required for this to work!
The newly released iOS 4.1 Beta 2 features new baseband for iPhone 4, iPhone 3GS and iPhone 3G which makes these mentioned phones locked on this new firmware. The guy who found the exploit used in Ultrasn0w 0.93 has confirmed that this new baseband patches the exploit and therefore it is highly recommended to stay away from this firmware for now if you rely on an carrier unlock.
