The Eugene area is a great place to explore Oregon wines.  Within just a few miles of town you can visit many different wineries, with many different approaches to tasting room style and types of wines.  Here is a good cross section of what's available:

http://www.pfeiffervineyards.com  Very warm reception, simply outstanding reserve pinots.

http://www.benton-lane.com  Once again, great pinots (is there a pattern here?) in a laid back setting

http://www.SweetCheeksWinery.com  OK, the wines here are only average, but the ambiance and view can't be beat. Friendliest place in the state.

http://www.silvanridge.com  Eugene's original winery and still the best.  Excellent wines at excellent prices in an elegant, relaxed atmosphere.  A staple for locals.

http://www.KingEstate.com  No tour of Eugene area wineries is complete without a visit here. Excellent wines, and facilities that would fit into Napa.

http://www.SunshineLimoService.com  Great tour company.  Drivers and phone staff are very knowledgeable about area wineries.     

 You should plan on spending 5 to 8 hours on your tour, visiting about one winery per hour or so (don't rush to see as many places as you can cram into the day - you'll forget them all).   Bring a lunch - there are many great places to enjoy a picnic along the way.

Don't forget - even tasting wine can impair your driving.  So bring a designated driver or hire a driving service.