Wine Tasting Tours in Napa or Sonoma

[bromion]

I have a group of 10-20 that wants to go wine tasting in Napa or Sonoma. I'm wondering if anyone here knows of any tour/charter services that leave from LA to either of these. Another option is for us to drive to that area then get a charter tour of some sort. Recommendations on these services are welcome! If you know approximate costs, that would be really useful.

Thanks!