Sackpipa (Swedish bagpipes):

Olle Gallmo's site
Some great insight into the Swedish bagpipes, including reed-making, playing techniques, history, and repertoire.

Norden Sackpipa Association of the Americas (NSAA)
A forum in English dedicated to the Swedish bagpipes and nordic culture.

PMN Music Creations
Peter Nowotnik is an Australian instrumentalist who plays a variety of ethnic instruments including a Swedish bagpipe of my making.

Uilleann pipes (Irish bagpipes):

Na Piobairi Uilleann (NPU)
Uilleann piping headquarters in Dublin.

Uilleann Obsession
Pat D'Arcy's site, dedicated to the Irish pipes.

Chiff & Fipple Forum
This forum can get a little crazy at times but a good resource nonetheless.

Uilleann Pipes Forum
Another forum focussing on the uilleann pipes.

Bagpipes (general):

Christopher Bayley's World of Bagpipes
Many examples of world pipes with descriptions and illustrations.

Oliver Seeler's The Universe of bagpipes
Descriptions, audio and illustrations of world pipes.

Pipe Show
A French web site featuring mostly European makers.

Cornemuses d'Europe et de Méditerranée
A French web site with multimedia content.

Rob Moore
Instrument maker based on Vancouver Island. Rob showed me much of what I know about pipe making.

Jean Blanchard
Piper and educateur based in Lyon. Jean specializes in French pipes.

Nyckelharpa (Swedish keyed fiddle):

The American Nyckelharpa Association
A great site dedicated to the Nyckelharpa.

Soren Akher
One of Sweden's premier Nyckelharpa makers.

Rita Leydon's site
Source for instructional DVD's on Nyckelharpa playing and building.