Gizmodo has posted a guide for extending the battery life of your shiny new iPhone 3G. Apple is notorious for pushing products with unimpressive battery life, and the new iPhone is no different. The battery isn’t user-replaceable, which means you can’t keep a spare, and the energy needs of the 3G chipset adds to the problem. Apple provides some useful tips on maximizing battery life for your iPhone. The tips include common sense advice that applies to nearly all electronic devices – turning down the brightness on your LCD screen, turning off radios not in use like Bluetooth, WiFi, GPS, and 3G, and setting Auto-lock to a minute or less will keep your devices running smoothly for longer.

We like to carry an extra USB battery like this one; you can also make your own like this one with an Altoids tin.