The Remote Desktop hosting feature is only available with Windows XP Pro. You can only use Windows XP Home Edition as a client and not a host.
Below, you will find some related Microsoft Knowledge Base articles that may be of interest:
How to: Configure a Computer to Receive Remote Assistance Offers in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;301527&Produc...
Support WebCast: Using Windows Remote Assistance
http://support.microsoft.com/default.aspx?scid=kb;en-us;826769&Produc...
Description of the Remote Assistance Connection Process
http://support.microsoft.com/default.aspx?scid=kb;en-us;300692&Produc...
Overview of Remote Assistance in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;EN-US;300546