Campaign Resources

Battletech Wiki
http://www.sarna.net/wiki/Main_Page

Wasat on the Wiki
http://www.sarna.net/wiki/Wasat

Map of the Inner Sphere
http://iscs.teamspam.net/pdf/iscs_3062.pdf

Mech Design Tool:
http://www.weirdozone.com/games/battletech/drawingboard.html

2.023 patch:
http://www.pryderockindustries.com/downloads/mech/tdb2_0_23_full_install.zip
http://www.pryderockindustries.com/downloads/mech/tdb2_0_23.zip

Downloadable mechs for TDB.
Originals: http://www.angelfire.com/games/battletechHQ/utilities/original.zip
http://www.pryderockindustries.com/downloads/mech/tdb_bm_3025.zip
http://www.pryderockindustries.com/downloads/mech/tdb_bm_3050.zip

Other Tools and downloads:
http://www.pryderockindustries.com/dl_mech.php

And lets not forget - you may want Tanks and Infantry
http://www.pryderockindustries.com/dl_vehicle.php