So look, we know the dilemma you're in. You nabbed that iPhone 3G or 3GS a little late in the game, and now you've got to wait until December in order to snag the iPhone 4 at a discounted rate. Lucky for you, Apple and AT&T have worked to give folks like you a little leniency, with existing AT&T users able to upgrade to the iPhone 4 "up to six months early." In other words, if your current contract expires at any point in 2010, you're now eligible to grab an iPhone 4 at $199 (16GB) or $299 (32GB) so long as you agree to stay faithful to a carrier you may or may not loathe for another two years. Good thing you've got until the