Partfoundry has announced that they are working on a real iPhone and iPod Touch GPS module. As of now, it’s all under development and the module isn’t even in a case yet.
It will pull your latitude and longitude coordinates from the module, then be able to proceed to map them in Google Maps.
The product is expected in February 2008. However, the iffy part is that the open source software requires a jailbroken iPhone or iPod Touch. When the next firmware release comes around and bricks existing hacks, what will happen? The device will be of no use until another exploit is found. We can only hope they will develop it to be used without a jailbroken iPhone/iPod Touch in the future.
You can find the link to a YouTube video demonstrating the module below.