I like to draw -- well, scribble -- while working with other people; that works well in my office, where I have a huge whiteboard. But if the other people are on the other end of a phone line, it's not so good.
I played with skrbl.com, which isn't bad (though I couldn't make it work with Safari or Chrome), but it's not ideal. What is?
(Oh...and I need to be able to work with people who aren't using Windows.)