If Cleartype is not really working for you (perhaps you are having compatibility issues with Google Chrome and Windows XP 64 bit), then you could try replacing the font renderer with free MacType.

Download from here:
MacTypeInstaller_2012_1022_0.exe – mactype – MacType 1.2012.1022.0 – Ultimate font Rasterizer for Windows – Google Project Hosting

It has lots of different modes and options – but you can use it to selectively replace the font renderer for a single process in “standalone loading” mode.

The result is quite impressive…