The US Hurricane Watch Net activated for Irene at 24/1300 August UTC on its usual frequency of 14325 kHz USB. Several stations in the southeastern US have shared net control duties. Right now, they have finished passing Advisory #18, and they are looking for stations in the Bahamas with information.
Irene is on a track right up the US East Coast, meaning a few miles/km of uncertainty can cause a great difference in where landfall ultimately comes, if it ever does. Also, the storm is becoming wide, with (currently) a ~60 mile radius of hurricane force winds. At this point, just about the whole US coast from SC up to ME has to watch this storm carefully. That's a BIG area.