The Cradlepoint PHS300 (US$179) creates a personal hotspot with a mobile broadband card like the many EV-DO data cards from carriers like Verizon.
I recently got a chance to test a PHS300 on a trip to Bonnaroo in Manchester, TN. Several of us were traveling to the weekend festival with iPhones and wireless notebooks via RV and we weren't sure if there was going to be Internet access in and around the camping areas. Sure enough, there wasn't Internet access, but there was a strong enough 3G/EVDO signal for my Verizon UM150 Broadband Access card (which I reviewed on 7 May 2008) to connect to.
Since I had configured it at home all I had to do was connect the VZW UM150 card to the Cradlepoint PHS300 access point and everyone was able to connect to its Wi-Fi signal and share the EVDO connection. It was excellent and super convenient. The PHS300 unit itself has an internal rechargeable Lithium Ion battery that only lasts for about 2 hours in my testing, so it's best to connect the included AC adapter to steady power – if that's an option.
The PHS300 includes a built-in firewall keeps you in control of your bandwidth, and WEP/WPA security allows you and your colleagues to work in a fully secure environment. The created hotspot is automatically password-protected preventing anyone in the area from hopping on your connection.