You need to be a little more specific by what you mean. Do you want to set up file sharing between the 2 computers? If so, then samba is what you want. You probably have it installed on your computer. If you type smb:///<ip_addr_of_xp>/sharename then you can see that share. For XP to see shared file on Linux you need to set up the samba server. There are ways to mount a windows share in linux. Search the forums for that.
Are you trying to share an internet connection from xp to Linux?
Also, a program called webmin ( www.webmin.com
) may be something you would want to look into. You can use it to administer your computer from a webbrowser.