Useful Links
Philatelic Traders Association (PTS) - Website of the PTS, containing details of all PTS members
Great Britain Philatelic Society - A great source for information on all things Philatelic
American Philatelic Society - As above but US focused
Barbados Stamps - Anything and everything you ever need to know about stamps and covers from Barbados
Graham Land Stamps - The go-to people for Cinderella's and Ex-USSR Republics
GBFDC - The Association of First Day Cover Collectors
GBCoverCollector - The definitive site for British Event Covers, Slogan Covers and Postmarks
RoyalEngineersCovers - Database of Royal Engineers First Day and Commemorative Covers