ChatterNoon for Chrome
More About ChatterNoon
* No registration needed. Pick a username and GO!
* Comfortable interface: draggable and resizable, show/hide with hotkeys.
* Integrated friend lists and whispers.
* Robust navigation thanks to its 2 chat tabs: One to talk with those in the current domain while in the other you can talk to those in your particular webpage.
* Very lightweight: uses latests available technologies to make it REALLY fast and light on your computer.