I upgraded to the new 3.0 software for my iphone, and this was succesfull. I jailbroke the 3.0 software, but after downloading an app with Cydia, the iphone will not reboot, and the screen displays the apple symbol, then the loading wheel will come up, and thats it. It will not reboot, and when i connected it to itunes to try to restore, it wont register the iphone anymore. I am stuck and not sure what else i can do. Any suggestions please? even when holding the power button and the menu button, the same thing happens.