Although the support for PCMCIA 3G cards has been a little sketchy you may be interested to know that the USB E220 I have from Vodafone works like a charm since the firmware update. You have to do the update on an XP machine but that rewites the new Vista drivers to the device allowing you to use it with Vista. There is no software to install as the device loads as a CDROM device and then auto runs the 3G device software from the device itself.
Link:
http://www.vodafonebusinessshop.co.uk/index.cfm?fuseaction=landing.usbmodem&WT.srch=1
-me