iPhone 2G 8GB to iPod Touch 8GB?

Well, I currently switched from a data package plan back to a standard plan within the AT&T Carrier Company.

But, I am left with an iPhone 2G 8GB that is SIM-less! So, I have decided to turn my iPhone into and iPod Touch, due to the fact that it is SIM-less and I don't have a data plan anymore.

I would like the right answers to how I can turn my iPhone 2G 8GB into an iPod Touch where I will only be able to use WiFi.

I hope I recieve answers from experienced people who actually did their homework and transferred an iPhone 2G 8GB into a fully working iPod Touch!

I will accept any possible answer such as Jailbreaking, Unlocking, and/or other processes, as long as it comes with a clear explaination and steps.

I want to transfer my iPhone 2G 8GB into an iPod Touch 8GB!