Originally Posted by penguin3107
In general mobile phones do not have an IP address assigned to them.
(There's a few exceptions to this, such as WiFi connectivity and iDen.)
Your mobile phone connects to the carrier's network over a specific transport and the carrier's network acts as an IP gateway between your handheld and the Internet.
The device itself doesn't really have an IP address of its own.
Using a service such as "What's my IP" isn't really showing you the IP address of your handhed. You're seeing a randomly assigned IP address of your carrier's IP gateway.
They do have an IP address when attached to the cellular network, but it is usually provided as through Network Address Translation (NAT), which is what makes your statement hold true.