If you think skype + screen -x is a replacement for Mac OS X screen sharing you should really try it. It's more like Skype + VNC, but a VNC that works much better.

This is the working pattern, you and the other side both see the same screen and can type and use the cursor at the same time, while doing high quality voice chat. So you have for example a terminal with vi opened and code while talking, then open Firefox to reload and check what happened to the application after the modifications and so on.

All this very fluid under a common DSL line. It's almost like being on the same room.