A few days ago I installed a Win client and tried to control a Mac with a Skype tunnel. This of course worked. But it is so slow. Why ? You cannot control the color and background information it sends from mac to win or from win to mac. In fact it sends all the time the whole image over the internet on every move you make on the remote screen, in full color and in full resolution ?! So it is completely not usable in a remote session over the internet from mac to pc or vice versa. But it does its job well between two Mac connections with Skype over the internet. Cross-platform ? Don't think so. Of course in a local LAN it works good because its a faster connection.