Cocoa applications have a really easy way to automatically do a smooth resize, going from one size to another with this nice sliding action. For an example, go to Safari and enable/disable the address bar (Shift-Command-\) By default, the speed of this resize is .2 seconds for every 150 pixels. However, there is a really easy way to change this speed. Simply go to the terminal and type this:
defaults write NSGlobalDomain NSWindowResizeTime x.x
What this does is set the time for every 150 pixels of resizing. A good value to see this is 2.0. That means two seconds for every 150 pixels resized. Just quit Safari, type that into the Terminal with 2.0 in the spot that says x.x, launch Safari, and hide/show the address bar. Much slower now :)
defaults delete NSGlobalDomain NSWindowResizeTime
Of course, if you've changed it on a per-application basis, you'll have to replace NSGlobalDomain with the application signature you've changed.
Mac OS X Hints
http://hints.macworld.com/article.php?story=200310242132275