GadgetLab has an interesting article about using an iPod Touch (or a foreign iPhone) with a MiFi local hotspot to access data and place Skype calls. As we get more accustomed to wireless data usage, one of the biggest hurdle for international travelers are the incredibly expensive data roaming rates. You have probably heard of stories where a customer gets charged tens of thousands of dollars for downloading something or simply use the web in the wrong country. With a local SIM card and MiFi, you can use your iPod Touch’s Skype capabilities to call or stream music (definitely not my first priority when I’m abroad).
That said, this is still pretty limited because you can’t call or use location-based services. It would be best if the iPhone supported UMA (like T-Mobile’s HotSpot@Home). You could then use iPhone+MiFi to place calls with your actual number without paying roaming charges, and possibly use the surrounding cell towers to find out where you are in Google Map.