A tipster just filled us in on this Sprint PHS300 Personal Hotspot USB device, made by Cradlepoint, that's essentialy going to be an EV-DO to Wi-Fi hotspot in your pocket. According to our tipster, it'll be available on March 1.
Just plug in your Sprint EV-DO card to the USB port (the ones that work on your Mac or Windows laptop, for example), and you can support up to four simultaneous clients over Wi-Fi. There's a 1800 mAH battery in there, which lasts an unspecified amount of time. It's fantastic if you're working in a group of, say, four Macbook Airs, so they can all share one 3G connection and not have to occupy their one USB port. [Thanks tipster!]
Data sheet here.