I will do my best to keep this as up-to-date as possible. Same rule in this topic as in the scenery topic; if you know of an aircraft that is being developed that is not on the list, please let me know. Please do not use this topic to bash any developer that I list. Some of them are not so good, and some of them are amazing; but they are doing something that most of are not.... designing products for the flight sim world.
------------------------------------------------------------------------------------------
PMDG: Boeing 737NG, Boeing 777, Dash 8
http://www.precisionmanuals.com/Qualitywings: Boeing 757-200/300
(Native FSX model and SP2 Released), Boeing 787-800/900
http://qwsim.comAirsimmer: Airbus A320
(Advanced & FSX coming soon)http://www.airsimmer.com/Level-D: Boeing 767-300
(Winglet update RELEASED), Boeing 757
http://www.leveldsim.comFlight Sim Labs: Airbus A320
http://www.flightsimlabs.com/Project Opensky: Boeing 767 Series V5, Boeing 787
http://www.projectopensky.com/Next Level Sim: Airbus A380
http://nextlevel.wepax.com/Aeroplane Heaven: DeHavilland Comet, Lockheed Constellation, Mitsubishi J-2M, Erco 415C Ercoupe, Boeing B-17,
Grumman Wildcat, Hawker Hurricane
http://www.aeroplaneheaven.com/ Aerosoft: Diamond DA20-100 'Katana', Robin DR400, Bombardier CRJ700/900, Falcon Ultra Light, Grumman F-14 Tomcat, Bell 205 Huey, Hoffmann H 36 Dimona, BAe 146,North American Rockwell OV-10 Bronco
http://www.aerosoft.com Flight Sim Nation: Air Tractor AT802F "Fire Boss", Air Tractor AT802F "Air Tanker"
http://www.fsairtractor.com/Enigma Simulations: Boeing 737-300/SP, Bombardier Challenger 300
http://www.enigmasim.com/ Project Airbus: Airbus A340-300
http://pairbus.com/AFS-Design: Airbus A330-200/300
(Released), Airbus A340-200/300/500/600
(Released)http://www.afs-design.de/ Captain Sim: Boeing 737-100 / 200
http://www.captainsim.com/---------------------------------------------------------
I think this is a good start. 
