XP Home edition won't connect to a domain. That portion of security has been removed.
You will need Windows XP Pro to do that.
XP Home can't be a member of a domain, but it can connect to domain resources. You do that the same way you map a network drive. You have to use a domain username / password for a user that has access to the domain resource (e.g. folder) you are trying to connect to. But, it can be done.
However, XP Home cannot participate in the centralized domain itself (for example, user accounts, account access and security, etc.).