If you are reffering to the cooperative missions also known as co-op then no, it has been confirmed that Modern Warfare 3 will not have a co-op component.
System Link
no but your just going to have to look on modern warfare 2 online
yes, just recently it was added online.
No. None of the Modern Warfare series have been 2 player online (aka. online split screen).
Modern Warfare 2 is a better game if you are going to play online.
So far in the Modern Warfare Series, there has been Modern Warfare One and Modern Warfare Two. A third is coming out in November.
no
no
It's not ever going to.
Yes, they have released Call of Duty: Modern Warfare 3.
.
No they will not