As you may know not all the network parts have installed in Ubuntu by default, e.g PPPoE.
While I'm searching for a solution to the problem (PPPoE with Ubuntu Linux) I have found short article about it.
Secret is here:

• Go to the url http://packages.ubuntu.com/intrepid/pppoe
• Download pppoe deb packet
• Install this deb on the fresh installed Ubuntu
• sudo pppoeconf
• type yours login and pass
• Congratulations!!!