Well if you and your friend are having Static IP then u can directly connect to his PC..otherwise in most the cases MTNL is providing Dynamic IP, so for that you can use a Software called VNC Enterprise Edition. You and your Friend should install this Software and then open the Port in your Router. For opening router Port you can visit (http://portforward.com/english/routers/port_forwarding/routerindex.htm) select your Router and follow the Steps..After the Ports have been opened from both the Ends you can use the IP Address which you Router is Assigned when you Switch on your Router and the Port number which you have Opened in Router. E.g if your Router is Assigened IP address 121.57.48.129 and you have opened Port # 7575 then you should use 121.57.48.129:7575 in VNC to connect to his Desktop. VNC Enterprise also Supports Drag and Drop File Sharing Facility. Which is not available in VNC Free Edition. Java Virtual Machiene should be Installed from www.java.com before using VNC Enterprise...

If you have any problems then feel free to contact me.!!!

there is no company on the router it just mentions mtnl

is there any general procedure to do it

go to internet explorer type 192.168.1.1 or ur default gateway address to open router page..
Username : admin
Password : admin or password     

else u ask MTNL to tell u the Router Password..!!!

Unless you open Router's Port VNC wont work..!!!

Rest everything is easy about VNC..