MTNL Triband in openSuSE 10.3

In windows do you have to dial in? If yes you will have to go to YaST->Network Devices->DSL Modems and configure form there. Make sure to tick the box which allows a non root user to connect using KInternet

No dial in, it gets connected automatically in Windows XP and IP address is dynamic.

If there is no dialer, that is modem on=internet on, then it should be the same in SuSE. Did you try browsing?
If it does not work, Open YaST->Network Devices->Network Card

Select your card->Configure

*img186.imageshack.us/img186/5439/n1ls5.th.png

Click on Hostname/DNS tab->uncheck update DNS via DHCP and enter
nameserver1 as 208.67.222.222
nameserver2 as 208.67.220.220

*img396.imageshack.us/img396/6929/n2ae8.th.png

Click on routing tab and enter default gateway as 192.168.1.1 (or whatever is the IP of your router)

*img403.imageshack.us/img403/6137/n3jt7.th.png

Click Finish