Ok, first, this isn't referring to Hot Spot coverage - a la T-Mobile at Starbucks. This is referring to the ubiquitous GPRS coverage that's everywhere you can get T-Mobile phone coverage.
For $30 per month you get unlimited wireless usage on their GPRS network. And they've just released the new Sony Ericsson wireless card that does both GPRS and WiFi. So that means with one card and $60/mo you can get unlimited GPRS *AND* Hot Spot access.
WOW! We've been paying $80/mo for our Sprint wireless cards for over a year now. This is a *major* cost savings. I'm nearly dumbfounded... and that doesn't happen often!