I was logged into GMail and noticed on my GChat side bar the appearance of a new icon... a mobile phone! I've pointed it out in the image on the left. It hadn't appeared before today and I turned on the "robots" icon lab feature a few days ago. So this is probably new! And pretty kool. I wonder if it is drawing from GMail's contact management, or from Google Voice. If you hover over this contact, an option to SMS appears. Pretty neat.