I've turned this feature on, and I have to say i was impressed.With Windows XP, ClearType delivers improved font display quality over traditional forms of font smoothing or anti-aliasing. ClearType improves readability on color LCD displays with a digital interface, such as those in laptops and high-quality flat panel displays. Readability on CRT screens can also be somewhat improved.
to turn on ClearType: http://www.microsoft.com/typography/cleartype/tuner/1.htm