Hey lightning49, glad I could help you out with Mpegger. When you open the program, in the main window there should be a preferences button. Here, you can change a few things, including bitrate and stuff. To change where the files go, just click on the "I/O & System Options", and you'll be able to the destination of the output files. The program shouldn't have any trouble converting aiff files. And I don't know of any incompatibility problems. Anyway, good luck with it!