Get Google Voice alerts on Windows 7 with GVNotifier
You can even make GVNotifier portable if you like -- simply create a settings.xml file in the same directory as GVNotifier.net.exe and it's ready to drop on your USB flash drive. The app will also run on Windows XP and Vista systems, though you'll need the .Net 3.5 framework installed.
Over at CyberNet News, Ryan Wagner's only real gripe with GVNotifier is how it handles contacts with multiple phone numbers. They're not displayed individually, so you have to click through each entry until you find the one you're after.
Download GVNotifier for Windows 7