No there is no time frame. My guess is within 2011, IF everything goes as THEY plan. All we know is they want it shut down and a ton of stuff is about to hit the fan in 2011. It's one of our greatest weapons against them and one of their greatest weaknesses. Freedom of information, speech and communication.
And I think it will be one of the last things to go, if it does go, because people have become so dependant on it. There will be a HUGE uprising against it unless there's a HUGE "reason" behind shutting it down.
But who knows for sure. And if something comes up that destroys their plan, which I believe is totally possible, then no worries, the witch is dead. :-)