Wednesday TapRoot Systems announced (.PDF), for "immediate implementation into carrier networks," WalkingHotSpot (WHS) client and server. The client will only work on WM and Symbian devices for now.
Of course, you won't be able to buy it yourself. Nope. The idea is for TapRoot to sell this to carriers, and then the carriers will incorporate it into their devices. In conjunction with the WHS server, which
provides carriers with the ability to manage and control subscriber accounts, authenticate WalkingHotSpot devices and clients, as well as collect subscriber usage information. This service allows carriers to offer a secure, controlled and scalable solution to their subscribers.AKA: carriers can / will use the server to charge for this. As if we don't pay enough for our wireless plans already, right?
Want voice / data? That's only available on HSDPA / UMTS devices. EVDO, though fast, will drop the data connection when a call comes in.
BTW, there's a (currently) free WM client called WMWifiRouter. It's on WM, though, and it's clear it's not going to be free once it ships. You can get a €5 discount on the final product if you try it and let them know (via a web form) if it worked on your device.