Hi Sandeep,
Windows itself provides you with Remote Desktop access. The following link will guide you regarding this.
http://www.microsoft.com/windowsXp/using/mobility/getstarted/Remoteintro.mspx
If you however want a standalone application, TeamViewer will be a good choice as per my suggestion. It is also free for non-commercial personal use. The following link will guide you there :
http://www.teamviewer.com/index.aspx
I hope this helps,
Regards,
tvks