Here in Japan, they've complicated the issue a little with this type of offering.
Basically it is a mobile WiFi spot. It is comprised of two parts of which both are battery operated. One is the 3G receiver. The other is a WiFi access point. The two are connected via USB and can operate on batteries for 2-3 hours.
With one of these, you can set up a WiFi spot just about anywhere in Japan. And then individuals can access the open WiFi spot which communicates through the 3G connection to the Internet. Sweet.
Of course you can plug in the WiFi hub if you want via a power adapter. That way you would have 24/7 access.
Things like this are great for those who have small meetings on the go.
Sounds alot like wmwifirouter, a program for WM smartphones to turn it into a mobile wifi hotspot. Unfortunatly my 8125 needs an updated version of WM before I can run it and I don't want to risk bricking the phone trying it...