There are some shareware. In my experience, I suggest AirfoilAnalysis shareware in versiontracker.com. Is the finest implementation of the Vortice Panel Method for windows and Mac I ever seen. Check it out. Obviously, it has all the assumptions and limitations of the Potencial Flow theory. That...
For subsonic part there are a some good implementations of Vortice panel methos to analyze airfoils - the finest shareware I tried is AirfoilAnalysis wich is in Mac and Windows plattforms. Maybe you can try it. It is in versiontracker.com