I have a modem/router so do not use pppoe.

but your first questions are easy....open a shell and run commands

uname -v (or for more info uname -a)

gcc --version

Thanks for the links!
Is there any difference in speed while using USB port than pppoe ?
My isp says the speed is anywhere from 256 kbps to 2Mbps dpending upon the net traffic.
And I am using pppoe right now but wud like to test USB.

Yes ! On connecting the modem to USB port I got this in lsusb:

Bus 4 Device 2: ID 1110:5c01 Analog Devices Canada, Ltd (Allied Telesyn)
Bus 4 Device 1: ID 0000:0000

But , as I said earlier I don't have the static ip details.

you can test speeds with a net tester choose the largest file your patience can handle

http://testmy.net/tools/test/d_load.php

My modem/router and my ISP allow pppoa which is slightly faster than over Ethernet

What is the diff betn ppooe and pppoa ?
My connection is thro adsl modem over telephone lines (broadband).

varaahan i think you are confusing with usb interface and ppp. better understand both are different. usb interface in the router is a alternate for the ethernet interface, it cannot work as pppo-a interface which is provided in usb-adsl modems. insteda pppo-a can be configured inside the router not in the usb-port. forget about pppoa as bsnl doesn't use that meathod and pppoe is only used in bsnl and is not slower than pppoa in any means. just plugin the usb cable in your router and system and do dmesg in the terminal it will give you idea about how it is connected. now open your network-settings and see if any new ethernet interfaces has been detected. configure ip-settings for the new eth interface and re-run pppoe-setup to use the new eth inerface thats all you have done.

On connecting the modem to USB port I got this in lsusb:

Bus 4 Device 2: ID 1110:5c01 Analog Devices Canada, Ltd (Allied Telesyn)
Bus 4 Device 1: ID 0000:0000

But netconfig gives eth0 only.

netconfig will not show any ethernet interface, use "ifconfig -a" to display all available network interfaces, typing ifconfig will only display working network interfaces so use -a option to show all interfaces. post also the output of dmesg command after you plugin the router cable in your system's usb port.