The new TiVo Desktop software for Macintosh (version 1.9) will check to see if you have Lame installed (packaged here), and if so, will let you play back your AAC files from iTunes through your TiVo and any TV or stereo system you have connected to it. This isn't documented anywhere, so it looks like someone either snuck it in, or they aren't ready to support it until 2.0, but for those of us who didn't want to re-rip our entire music collections to play them back through our TiVos, it's great news.