O2 has published a guide to not getting the iPhone 3G this Friday. It thanks visitors for their interest in the device, but warns that unprecedented demand means that it will be the end of summer before everyone who wants an iPhone 3G gets one. As expected, each O2 and Carphone Warehouse store will have on average just a few dozen handsets, though that will depend on store size and location. Apple will also be selling iPhones at its stores, but only for new customers, not those upgrading...