How can I convert AC3 audio files to AAC? I had a friend with a BluRay drive extract the audio from my copy of a concert BluRay disc into AC3 files which he returned to me, but now I'm not sure what the best way would be to convert those AC3 files into AAC files.

I've read that it's not possible to go directly from AC3->AAC, but instead have to use WAV as an intermediary; AC3->WAV->AAC. I can probably figure out how to do this, but why should I be the one to make two steps? Is there software already available (free preferred, but not required) that will simply let me plug in an AC3 file and get an AAC equivalent out?

When I say AAC equivalent, that means identical channel setup to the source AC3 files by default, but perhaps also preferences to constrain it to 2 channel or anything else I'd like.

I've already tried using Handbrake and Max to no avail.
VideoLAN can do this. Select "Streaming/Transcoding Wizard" from the File menu. Choose "Transcode/Save to file". On the next page click "Choose" and open your AC3 file. On the next page tick "Transcode audio" and choose "MPEG 4 Audio" and choose the desired bitrate. Click "Next", choose "MPEG 4 / MP4", click "Next" again and "Choose..." where to save the file. "Next" and "Finish".

The file VideoLAN creates has the extension .mp4, change it to .m4a and there you go.