Look up at the sky -- is it falling? It sure seems as if that kind of doom is imminent, at least if this whole iPhone 4 pre-order situation is any indication of future tragedy. We've received hundreds of tips this morning from friends near and far that iPhone 4 pre-orders aren't going through, though a few of us here on staff were able to get a confirmation during the wee hours of the morning. From AT&T in the US to O2 over in the UK, it seems that just about everyone ambling to get their name on a future iPhone 4 is experiencing a great deal of frustration. AT&T's servers seem to be comple