We currently offer a massive range of downloads for FSX, as well as older flight simulator add-ons for the ever-popular FS2004, FS2002, CFS3 and now becoming ever popular with dediced virtual aviators is Laminar Research's X-Plane series.
I don't think this has been posted here, so for those who are interested but haven't seen it elsewhere:
FSW or FSWeapons is an add on in early development that will implement all kind of guided weapons in FSX, air to air and air to ground, and hopefully in the future even SAMs and AI-planes shooting back. For the moment there will only be single player mode, but we have ideas how to enable multiplayer. You can read about it here: http://sul37.blogspot.com