What is the Difference between iPhone 1G and iPhone 3G?

The difference between an iPod touch and an iphone 3G is that an iPod touch uses Wi-Fi hotspots to find your location, doesn't take pictures, doesn't text message (SMS), and is not a phone. The iphone 3G on the other hand uses GPS to find your location, takes and saves pictures, text messages, is a phone, and is available with AT&T or T-Mobile service.