As it’s still a big question if the next iPhone will have GPS out of the box, iGpsd developed a solution for our current first gen iPhones. They already had a working version based upon the Holux M1000, which you can order from there website for about 100$. The downside on this version is that it’s a bit bulky and doesn’t integrate very well next to the iPhone. Today they released a movie of more slimmed down working version.
» Working GPS module from the iGpsd team