If you're tired of typing in the same computer name over and over in the Finder's Screen Sharing window, create a shortcut. The easiest way I found was start Safari, type vnc://servername, and then drag the shortcut to your desktop or wherever. Add the server to your keychain, and you have a one-step screen sharing session.
Final tidbit: Screen Sharing will connect to machines that have been shared via Apple Remote Desktop sessions.
[robg adds: This hint is a sort-of corollary to this one.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071027144126105