drawing in realtime for messaging

Hello everybody,
I am an architect and i am supposed to work a design project at distance. Please reccomend me a software that will be able to collaborate on a sketch in realtime, just like chatting on Yahoo Messenger or similar. What i need is that both myself and the other architect to draw/erase on the same sketch, and the result to be instantly visible.

Thank you,
Dan

I've never seen a software which can do this in realtime.
With ArchiCAD and Teamwork/BIM Server you can work on the same project,
but you can't see realtime what your partner is drawing. The sync must be started manual, so that there is a delay of some minutes.

Maybe a good alternative is desktop sharing with f.e. teamviewer.

A combination of both should be very comfortable. When you discuss some
points you do this with desktop sharing and in the meantime you work on the same project.

Thank you. I believe i'll go for the teamviewer, best.

Regards, Dan