As you'll recall, a few months ago I posted instructions on how to use the Verizon PC5740 pcmcia EVDO modem. At that time, there was an incompatibility with the VZAccess software and Windows Vista.
I'm happy to report VZAccess v5.8.2 for my PC5740 works very nicely with Windows Vista RC1. If you need to download VZAccess, see http://www.vzam.net. Keep in mind there are different versions of VZAccess associated with different cards or chipsets.