If you go the The Sim-Outhouse forums, a lot of the developers (freeware and payware) hang around in there, or at least visit there a lot. They have dedicated forums for the different sections of designing for Flight Sim. I would recommend going there and taking a look through the forums. Could be worth signing up so you can get to ask questions/request help yourself.
Unfortunately for me. At the moment, my account there is having problems and the forum administrator has never responded to my requests to fix it. This has been ongoing for a year or so. I still go in there and visit the forums, but I just can't post anything.

Mark

Is there anything there about sounds?
I guess so. I haven't looked into gauges as much as I have with modeling and textures.

Do most developers get their aircraft sounds from actually recording the aircraft?
I know that some (not sure how many) of the payware developers do. I guess the same applies to freeware devs. You'll just have to ask.

Mark