I found a freeware skin that resembles the iPod interface, it's called the uPod! Here's the link:
http://www.freewareppc.com/misc/upod...ayerskin.shtml
Copy the extracted files to Built-In storage on the PPC, so that WMP can recognize and auto-import the skin
About changing skins, I have Pocket Windows Media Player 10 installed, and you need to click Tools>Options at the bottom of the screen, then scroll to the right to Skins, then cycle through the skins available and then hit OK to implement the changes.