I haven't seen this one posted yet, but its a nice feature of X, and worth mentioning it again.
When you have cable connection and click a "Listen" link at shoutcast.com, a .pls file is downloaded and played in iTunes. For every new station you select a new .pls file is downloaded.
Here comes the cool thing..
Open a Finder window in column view mode and find a .pls file (not the one that is playing in iTunes). Press the play button in the Finder window and the .pls file will start to play!
You can open other finder windows to with other .pls playing, however, the Finder window in the foreground will be heard. The other(s) continue playing in the background and can be heard when the window is clicked on. The iTunes stream keeps playing all the time.
There is limit in active streams you can have open, but I haven't found it yet. I've got 3 stations simultaneously running in their windows, and iTunes is also playing.
That does it for me...
[Editor's note: This is, of course, one of the features of the column-view Finder mode, but it is a unique application of that Finder feature!]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020525100558135