We did an excellent wine tour with www.trekkingchile.com (=Casa Chueca) from Talca, the main town in the Maule Valley, one of the biggest wine-producing areas in Chile. The tour was 25,000 Pesos per person for a private tour. We visited 2 boutique vineyards, with explanation and two wine tastings per vineyard. The price included transport, tasting and an English-speaking guide.
Wine tastings can also be arranged cheaper by going to (different) vineyards on public transport. Apparently there are only two vineyards that accept individual tourists. Both are located in San Javier and reachable by bus and collective. Wine tasting in each is 5000 Pesos for 2 wines. The tourist office in Talca is very helpful and can give you further information.
We stayed in Hostal Pehuenche in Talca, 5 Oriente 1184, between 1 North and 1 South. A big double room with balcony and breakfast was 14,000 Pesos.

For more information, see our weblog
Westwards from Japan
http://westwards.typepad.com