I came across this today while browsing some plist files. You can enable a "Bonjour Browser," which allows you to add list of computers you can connect to via the new ScreenSharing application (hiding in /System/Library/CoreServices) in Leopard. To enable this, run the following command in your terminal:
defaults write com.apple.ScreenSharing ShowBonjourBrowser_Debug 1
Now relaunch ScreenSharing.app, and you'll have a nice browser window, showing computers whose screens you can share. You can also add a computer to the My Computers section (via the checkbox at the bottom) which leaves the connection in the list.
[robg adds: We discussed the screen sharing app in this hint.]

