Ariano Hermanos S.A.

Makes a range of reds and whites under the Ariano and Vina Constancia labels. Includes descriptions of wines, an award list, a company history, and a list of importers.
http://www.arianohermanos.com/

Establecimiento Juanicó

Produces a variety of red, white, and dessert wines under the Don Pascual label. Contains product descriptions, award lists, a company overview, and some Uruguayan recipes.
http://www.juanico.com.uy/

Pisano

Family-owned producer of a range of reds and whites, including Tannat, Cabernet, and Chardonnay, in Progreso. Features product descriptions, a map of the country's vineyards, and a company history.
http://www.pisanowines.com/

Toscanini Wines

Winery in the Rio de la Plata region, with a range of products including Tannat, Chardonnay, Cabernet, and Merlot. Describes the products, vineyards, winemaking, and history. [Flash required]
http://www.toscaniniwines.com/

Calvinor

Produces a range of reds and whites. Includes product descriptions, a company overview, and a list of awards.
http://www.calvinor.com/

Wines of Uruguay

The Uruguayan Wine Exporters' Association provides descriptions of wineries, a list of awards, and information about Tannat.
http://winesofuruguay.com/