Does anyone have and recommendations for a limo service that does wine tours? There will be 8 of us, and we want to do a private limo service. Any suggestions would be greatly appreciated. Thanks!

Evans has been running airport service for years from the Napa Valley and Vallejo to SFO. I see on their web site they also do tours, so it might be worth a look:
http://www.evanstransportation.com/index.shtml

Are you into drinking and seeing some nice scenery or are you serious wine people?