Spanish Civil War Resources Site
Spanish Foreign Legion (Spanish)
Abraham Lincoln Brigade Archives
Forgotten Heroes: Spanish Resistance in France
Historias de la Historia (Spanish)
La Guerra Civil Espanola/The SCW
Las Brigadas Internacionales en la Guerra Civil (Spanish)
Los Tiznaos {Homemade Armoured Cars!}
SCW - The Gauntlet (Mark Hannam's excellent wargamers guide to the SCW!)
For wargamers - don't forget that Peter Pig make a superb range of SCW figures in 15mm!