Correspondent Josh Rafofsky drew my attention to this Apple Kbase article which describes how one can use a "third-party" application to change the file type of your AACs to make them bookmarkable. "How about a killer AppleScript that can do it for you?" asks Josh. I had to haul out my "Tao of AppleScript" to remember how to change file types, which I haven't done since I was regularly using OS 9. Make Bookmarkable will change the file type of the selected AAC tracks to "M4B", thus making them bookmarkable. Works at my house. I suspect scripts like these will be popping up all over the place in the next few days.