Just read in TechCrunch about a new itouch app by UK-based Truphone that allows you to make phone calls on your itouch if you have WIFI access. Sounds pretty good. Calls are free to other itouch users as well as other supported mobile devices and low rates to those outside the system, much like Skype. What is interesting to me here is idea of taking an itouch and getting near iphone capabilities.
Still missing is GPS, but check out this project adding GPS to the itouch and the first iPhone...
So, between being able to make call, plugin GPS, all we need now is a way to connect a 3G card and we have all but incoming call iphone!