The third generation introduces new hardware that is found in the iPhone 3GS. (increased RAM, better CPU & GPU.) The third generation also includes the voice control support from the 3GS which apple calls "VoiceOver".
Well... the difference between the 1st generation iPod Touch and the 3rd generation iPod Touch is SLIGHTLY different. The cases will STILL WORK!!! (you are relieved :) ) The difference between the two generations is that the 3rd generation is slightly slimmer that the 1st. The thing is the cases made for the 1st generations might me a little big... (by a few centimeters!)
there are 4 generations of the ipod touch
The difference in iPod generations is what they updated. They could have updated the speed of the device, added new features, fixed bugs, etc. And as always, it is recommend to always update to the latest version, unless the latest version has more bugs or problems.
The I-pod touch has a touch screen.
There is none. iPod Touch 3G IS third generation.
The difference is that a 3rd generation iPod touch has voice control if you purchase the "Apple Earphones with Remote and Microphone". The 3rd generation is also faster and has a better processing system.
The i-touch has a touch screen, the i-nano does not.
Storage capacity is the only difference.
All generations above the previous generation are usually better in iPods. In this case, the iPod Touch 3rd generation is better than the 2nd. The difference is that the 3rd generation has bluetooth, but you can install that on your 2nd generation. There is not difference in speed Apple pretty much repackaged the 2nd generation adding the bluetooth to it though.
well the 4th can take video the 3rd cant ooommm i just reccomend the 4th for everbody :)
There are currently 4 generations.
You shouldn't use an iPod Touch case designed for the second and third generations on a fourth generation iPod Touch. The fourth generation iPod Touch has a camera and microphone, so the third generation case would cover both of those up, and would not fit it anyway.