Try THIS PAGE
(Only problem is that you will probably have to reinstall Linux if you already installed it)
One extra thing when doing that is that you should keep a copy of the Linux bootsector that you make, incase you reinstall WinXP later.
I used it for WinXP and it worked a treat, and I am also a bit of linux newbie myself, so it isn't hard. I much prefer using WinXP to using a linux bootloader, since this way you will never lose your Windows. Let me know if you have any problems getting it to work.