I have been delighted to discover that not only does Leopard (MacOS X.5) have a built-in VNC client, it supports screen-scaling out of the box. Connect to Server (Finder >> Go >> Connect to Server, or Command-K) has a handler for the vnc:// protocol handler that invokes Screen Sharing as a VNC client.
Apple win again.
Macworld has an article that outlines the power of Screen Sharing as more than just a VNC client.
