I made vpn connection in widows xp and opend 1723 port now i want conect with this vpn conection by other computer but not connecting plz help me what i need more to do ?

how are you trying to connect to this computer...over the internet? If so, are you connecting by IP or hostname? Do you know your network's public IP address?

i am trying to conect by host name yes i knwo my ip. actulay i have 10 computer diff places i want concect with one i dont have exprerience about this ?

Ok, start by reviewing this Microsoft article on how to setup a VPN connection on XP.
http://support.microsoft.com/kb/314076

You mentioned that you already opened port 1723. By the way you also need to open Protocol 47 (GRE).

If you want to connect by hostname, I assume that you already setup a host name on a public DNS zone, yes?

Also, you may not be aware of the VPN limitation of XP. It only allows one inbound VPN connection. If you need more, you'll have to run Windows Server.