Try this site Jibbs
There are a lot of Font sites out there and most of them have a help file on how to download them and instal them but just in case I will tell you how I do my downloads.
Fonts usually come as a zip file so they will need to be unzipped somewhere on your computer where you can easily find them - (make a folder on your desktop called unzipped perhaps ? ) Anyway unzip your font then go to Start/Settings/Control Panel and you should be able to see a folder called Fonts. Click on your Fonts folder, when its opened look at the top where it says File and click on that - you will see Install new font - click on that. Then you get a little window and you have to search your folders to find where you placed your unzipped font. When you find it click on it and it should appear in the 'list of fonts' click ok and thats it. When you open Word you can scroll through the fonts as usual and it will be there for you ......
Of course I don't have XP but I would imagine that a Fonts folder is somewhere in control panel where ever that may be in XP
I hope this helps