I've been working on creating an AppleScript that joins selected tracks together, be they MP3 or AAC, and then uses ChapterTool to create an enhanced AAC audio file of the joined tracks (it doesn't create enhanced files from an MP3 joined track, but still it will join MP3 tracks together as one). The result is Join Together. This is an applet that, first, let's you join MP3 or AAC tracks together (QT Pro is required for the AACs) and then then optionally let's you create a "chapterized" audio file--that is, an enhanced audio file--using Apple's "ChapterTool". Correspondent David Duke clued me into using QT Pro for joining AACs. MP3s use the UNIX 'cat' command. But ANYway...after the joined track is complete the script will use "ChapterTool" to create an enhanced "chapterized" version of the joined track, enabling iTunes 4.9 to skip to the various songs that have been joined. This is v1.0 and works great at my house. Of course, there may be exceptions so let me know.
Source >>