Here's a naive Mt. Gox websocket client I wrote in python: http://pastebin.com/FH6eWhFm
By default it just prints out trades as they happen, but you can modify it to do whatever you want.  If someone really wants an event-based version or something to make it a little easier to work with, you might be able to convince me (with a few bitcoins ) to put something together with pywsc or something.  I may eventually release an executable jar (clojure/java) file for those willing to buy a copy that will give you a GUI to view live trades and depth changes (though mtgox's websocket is still quite buggy in respect to depth changes...there would be a button to let you do manual refreshes as well).