playing online - 360

Guys,
I am very new to online gaming and this is the first year after owning every year of this game that I have gone online.

can u help me...

First up is probably a very stupid question but can you chat to your opponant via the headset when playing on line? i havent been able to do this as yet.

Also, I have played 8 games online....2 of them have not been finished, the first in OT where my connection dropped out (damn Telstra) and second where I was up by 30 at the start of the 4th and my opponant bailed on me.

How to the rankings and ratings work?

Also would love to get into a league if anyone has a spot open for an amature.

Thanks
Martyboy