A guide to endgame tablebases. - Answers common questions regarding the use of endgame tablebases. - http://horizonchess.com/FAQ/Winboard/egtb.html
Endgame Tablebases Online - A project to make 6-men Nalimov Endgame Tablebases available online on eD2K/KAD network - http://kd.lab.nig.ac.jp/chess/tablebases-online/
Nalimov Tablebase Server - Online query of the server. All 3,4, and 5 piece endgames are available. For programmers; the service is also accessible from within your own application. - http://www.lokasoft.nl/uk/tbweb.htm