Ok, I've scoured the forum prior to posting this thread and while I may have missed it, here's what I'm seeing. I have created a development profile, all my certificates, an AppID, and have registered my iPod touch. Because it was on OS 1.x, I paid the $10 (+ tax ) for the 2.0 upgrade and have re-registered it in Xcode and done all that. I took one of the sample applications (BubbleLevel) and have set it up with Active SDK=Device-iPhoneOS2.0, Active Config=Debug. When I download it to the device, it says: "Your mobile device has encountered an unexpected error (0xE8000001) during the install phase: Verifying application. Try disconnecting and powering off the device; then power the device on and reconnect it." I'm not sure what an E8000001 is, but it smells like a certificate problem - it gets all the files to the device OK (I see the copying described) but when it checks on the device it's not happy. Any specific thoughts?