Reads this:
How to hack your iPhone and this:
Steve Jobs has said that he’ll be fighting against those companies that allow you to unlock your iPhone.

This can be done with the video iPod, it does everything an iPhone does, except you cannot use it as a phone.
When you are not close t a WiFi access point, the iPhone can use AT&T's data system to still access the Internet for mail, etc.
The iPod and unactivated iPhone need to be connected to a WiFi system to access the Internet.