Turn on ClearType Font-Rendering Technology
 

I found this in a few different places around the 'net - hopefully it's helpful:

Turn on ClearType Font-Rendering Technology

Get that extra text clarity you've always wanted. The incredible Microsoft ClearType technology can be enabled in Windows XP to smooth all fonts at all sizes, making the whole system so much easier to read.

• Click Start, then Control Panel, and then click Appearance and Themes.
• Click the Display icon, then the Appearance tab, and then Effects.
• Click the Use the following method to smooth edges of screen fonts check box and select ClearType from the list.
• Click OK, and then click OK again.