Amazed by Microsoft's Remote Desktop software that allows me to control my Windows PCs from my iMac, I'm thinking I bet Apple have this built-in in the OS. Yup, it's called Screen Sharing in Leopard. Apple made it even easier. All I need to do is to enable "Screen Sharing" on the target Mac (in my case my Macbook), allow access for specific user(s) (this is for security. I you don't do this, anybody with a VNC client on the network can access the Mac), and voila. I logged out from my Macbook, went to my iMac, opened up Finder, and my Macbook is listed on the Shared computer list. All I needed was to click "Share Screen," and a Screen Sharing app started, and I can log-in to my Macbook via my iMac.
Again, probably nothing new for some computer networking experts, but I still find these features to be awesome. Having multiple computers used to force me to go to different computers to control them. Even with a KVM switch, it's still a hassle. Now I can control everything from 1 computer. :)