A friend sent an email exhorting me to take advantage of ClearType on Windows XP. (Hmmm, he's a newly-minted Microsoft employee... the beginnings of a subtle intra-friend marketing push?) I've tried it in the past, and been very impressed. I don't use it because I switch back and forth from LCD to CRT a few times during the course of a day, and ClearType doesn't look good on CRTs. I expect to be all LCD all the time in a week or so, so I'll give it a real try then.
But I was reminded of Steve Gibson's Sub-Pixel Font Rendering Technology page. It's got a lot of good information about the technology. It also has Free & Clear, a demo of the concepts of sub-pixel rendering. Perhaps most surprising about the app is that it is Windows application but only 35Kb in size, complete. It's that small not because there's a 2Mb DLL alongside it, but because it is written in assembly language, just as all of Steve's software is. I think he's nuts, but I admire his dedication.