Hey you old guys, I have a Question for ya!

if u are runnng tiger inap then you will need to go to versiontracker and download stuff it. It will un zip the .sitx. ( if im not mistaken apple did not put stuff it in the bundeled software on 10.4 so your computer would have no way of "unzipping" the sitx..
and remeber when any one says "right click" they are saying control + click...

OK. Let's back track a bit.
Do you have Stuffit installed? If not download and install that first, there is a free version available. Stuffit unpacks sit files.
http://www.versiontracker.com/dyn/moreinfo/macosx/182
Once unpacked WMP should install without a problem.