SimHQ.com - home to the Rowan Battle of Britain forum - use Battle of Britain link under Flight Simulations  

Current listing of Mods etc - via the above forum.  

BDG - the BoB/MA Developers Group - working with the released Rowan Source Code to further develop the
Sim - related to the SimHQ.com forum.

VIPER - the best visual effects: Smoke, Smoking Tracers, explosions, File and Skin Manager and recently
a new Emil cockpit..

CPT FARREL - skins for all the aircraft in the Sim - a mammoth task !

MAUSUSER - clouds, grass, skins, props.

SOUPDRAGON - Radio Sounds plus some videos for the Sim, including a lovely 60sec 1969 BoB film intro.

MOSI - Gunsights and damage effects.

BADER - Patches, skins, terrain, effects, sounds, cockpits.

AXA - Links to downloads, terrain and more.

JOE STALLIN - (under PC Sim resources)  - various goodies, includes Wolf's BoB film gunsounds .

STENNEG - Download via forum page of Hendon Me109E skins.

PLUMMERX - very good site about the actual Battle of Britain. . . .plus the BoB theme!