Comparison and differences between the new iPhone 3GS and the iPhone 3G (aside from the fact one is $99 the other starts at $199)

 iPhone 3GiPhone 3G S
Price$99 8GB ($299 for ineligible upgraders)$199 16GB, $299 32GB ($399 and $499 for ineligible upgraders)
Processor412MHz ARM 11Unknown, “on average up to twice as fast”
Graphics capabilityOpenGL ES 1.1OpenGL ES 2.0
Camera2.0 megapixel fixed focus3.0 megapixel autofocus with macro mode and auto white balance
Video recordingNone30fps VGA with on-device editing capability
Voice controlNoneDialing, music control
Nike+ supportNoYes
Wireless technologies3.6Mbps HSDPA, WiFi, Bluetooth 2.0 + EDR7.2Mbps HSDPA, WiFi, Bluetooth 2.1 + EDR
Water- and oil-resistant finishNoYes
Integrated magnetic compassNoYes
Included headphonesStandardInline remote for music control
Battery lifeUp to 5 hours talk time / data on 3G, 10 hours on 2GUp to 5 hours talk time / data on 3G, 12 hours on 2G
 Up to 6 hours data on WiFiUp to 9 hours data on WiFi
 Up to 24 hours audioUp to 30 hours audio
 Up to 7 hours videoUp to 10 hours video
Dimensions115.5 x 62.1 x 12.3mm115.5 x 62.1 x 12.3mm
Weight133 grams / 4.69 oz.135 grams / 4.76 oz.

(source: engadget)