Modifications and Add-Ons

Comiato Headquarter
Contains utilities and add-ons for flight simulator and x-plane.
http://www.pentaonline.it/comitato_hq/index.html

How In the World?
Developers of flight simulation add-ons.
http://ftp.avsim.com/library/esearch.php?Name=&FileName=&Author=how+in+the+world?&Description=&CatID=Root

MLK Air Base
Add-ons and improvements for flight simulators.
http://www.mlk-airbase.wz.cz/

Project Magenta - High End Flight Simulation
Creates flight simulation add ons.
http://www.schiratti.com/

RDB Flite Site 2000
Features software, downloads, accessories, and hot links to Flight Sim sites.
http://www.geocities.com/capecanaveral/cockpit/7140/

The Scenery Hall of Fame
Includes flight simulator scenery add-ons.
http://www.scenery.org

Simmers Paint Shop
Offers information and resources for making repaints and skins for various flight simulators. Also a meeting place for repainters and skinners of various communities.
http://www.simmerspaintshop.com

Society of WWI Sim Artisans
Creates skins and planes for World War One simulators.
http://www.swwisa.net/