iTunes server is in meltdown. I just hung up with Theresa from Apple. If your phone won't finish the update, don't worry, your not anyone special today. Apple says there is nothing wrong with your phone or your Mac/PC. The iTunes server is overwhelmed. If your iPhone is a brick right now, they recommend unplugging it regularly and plugging it back in until you get a completed connection to the iTunes server.
She did apologize for the fact that my phone is simply a paperweight at this moment.