iPhone 3G w/o SIM messaging app I would like to use our jailbroke iPhone 3G with NO SIM. Is it possible to use the built in messaging app that Apple supplies on this iPhone wit no SIM?  

Is this possible to do or do I need to use one of the other free text apps?  If it's possible could some one please post the instructions.

Why is it that our iPad is able to use the messaging app but I can't with the NO SIM 3G?

Edit:
I previously thought I had the iPhone 3GS. I recently edited because I found I have the iPhone 3G (not S)
Your iPhone 3G isn't eligible to upgrade to iOS 5+ which use iMessage, as a supplementary (or primary) means of messaging, and which does not require use of SMS (cellular transfer). 

As a result, you will need to rely on a 3rd party app (that supports iOS 4) to do your messaging. A Google search revealed that there are still a number of texting apps that support iOS 4.3 (which your phone should support) such as:  https://itunes.apple.com/us/app/textplus-free-text-group-texting/id314487667?mt=8&amp;ign-mpt=uo%3D4