Validation (HTML/CSS)

Hi people,

I recently went to the W3C homepage and was really glad to find a Validation service for CSS and HTML4.
I have a pentII 400 (128 meg ram) but I do not have my own domain on the net. I was wondering if I could use the HTML4 validation feature offline at home. I downloaded a zip file which said it had the source code but I was completely dumbfounded on how to set it up or if it could be set up for offline use.

Can I use it offline at home or does it require me to have something expencive to be able to use it. (as most things do these days unfortunatley)