Cell Modems

Sprint offers an express card modem for macs. We don't offer much support for it. I believe one of the usb modems we offer also works on the mac. I'm not entirely certain about it though. The express card one works well, when I played with it in training.

Just get an unlimited data plan and tether it with bluetooth.

Tsice is, I believe, recommending you purchase a phone that can be used to "tether" via a USB cable (or Bluetooth) as a modem, rather than purchasing a card.

In regards to the protocol question. There are 2 network types in the US. CDMA which Sprint, Verizon and Alltel (and other more local networks) use. And GSM which AT&T and T-Mobile use. The choice depends most on your primary area of usage. CDMA uses EVDO for their 3G data network, while At&t uses whats called HSDPA (T-Mobile hasn't upgraded to a 3G network yet). EVDO has been around a little bit longer and thus is more widely available, at least in the US. If you plan on traveling to Europe, GSM would be the way to go, as GSM is practically the only network type used outside of the US.