International Skat Players Association: Organizes tournaments and promotes the game worldwide, with local chapters in a dozen countries.
Schafkopf Group: The rules, tactics and variations for the Sheepshead/Skat/Doppelkopf/Schafkopf game family.
Schafskopf: Rules and strategy for the three-handed game variety.
Sheepshead Association: Free group offering game rules, glossary, history, and related resources, with tournament and open play news.
Sheepshead Central: News, tournament updates, event photos, online polls and an active message board.
Sheepshead Home Page: The playing deck, rules, scoring, and strategy tips.
Sheepshead Optional Doublers: Optional ways of scoring.
Sheepshead Page: Game history, rules, and tips.
Steiner's Sheepshead: A weekly tally of results from an ongoing Madison, Wisconsin game begun in 1996.
The Rules of Skat: Scoring, bidding and special conventions.