Windows XP has a feature called "Clear Type" designed for exactly this purpose -- to sharpen up text with LCD monitors. It's off by default -- you have to turn it on. Where/how? I don't know, as I don't have XP yet, but someone on here will know and post an answer very shortly, I'd guess. Or just go to your Help menu on your computer and type in "Clear Type." Should be able to find out all about it rather quickly.
This is all assuming, of course, that nothing is physically wrong (defective) with the monitor or vid card and all your settings are okay. Everything else look okay? Web page images, pictures, etc.?
Also, as Wobble is probably alluding to, running LCDs at anything other than their native resolution can adversely affect the image quality. Running it either at native res or the next closest res is recommended, I believe. Hope this helps. 🙂