Here is a list of popular IRC clients that you may use to access the edublogosphere.com room.

For the Mac, I use Colloquy. I find it to be best IRC application bar none. It’s tightly integrated with Mac OS X and I’ve had no trouble using it on Leopard. They even offer a version of it for the iPhone.

On the Windows side, all I’ve ever used is mIrc, which I don’t terribly like. It’s demoware, so I’ll take a good suggestion for a free or open source something to put right here in its place.

Not sure about the Linux side…