Archives, Libraries and Museums
Swedish
Krigsarkivet
Swedish Riksarkivet
Swedish Army Museum
Swedish Kungliga Bibliotetek
Danish Rigsarkivet
Danish Tøjhus Museum
Norwegian Riksarkivet
Norwegian Forsvarsmuseet
Swedish Archive Information
Service
Chakoten (Danish
Military History Society)
Royal Danish Garrison
Library
Battle and Order of Battle Information
The Nafziger
Collection (Period Orders of Battle)
Battles
of Great Northern War
Swedish
Battles
Nick
Dorrell's Great Northern War Pages
Books and Magazines which cover the Period
Acedia Press
(Books and other useful information on Swedish Uniforms,Colors
and Standards)
Gauntlet Publications
(Source for Russian books and magazines on uniforms, etc.)
Pike and Shot Society (Publishes the magazine
"Arquebusier" which has many useful articles dealing
with Cossacks, the Polish-Lithuanian Army and the Russian Army,
as well as the Danish and Swedish Armies - highly recommended)
Årnfelts
förlag ( Gå På Rules and Army Lists)
Navy
Russian
Galley Fleet 1714
Russian Navy
History
Reenactment Groups:
Christianssand Artillerie
Compagnie
Fredriksten Artillerie Compagnie
Kong Fredrik IV Tambourafdeling
av 1704
Age
of Marlborough (War of Spanish Succession Reenactment
and Discussion Group)
Polish
Artillery
Preobrazhenskt
Life Guards
Arkeliet 
( Danish-Norwegian Artillery and associated
equipment, tools and ammunition)
Norwegian Fortresses
Fredriksten
(Halden)
Kristiansten (Trondhjem)
I would appreciate hearing of new sites that may be appropriate to add to this list, as well as any links that may no longer work.