An XDA developer forum member has posted for download Apple iPhone 32 X 32 pixel icons and a Phonealarm skin to customize your Windows Mobile based Pocket PC.
The icons can be used with a software called cLaunch (available for download here), which is a free plugin launcher with the capability to skin icons for Windows Mobile.

Here’s the tutorial on how to display the icons with cLaunch for your Pocket PC.

If you look at the picture posted below, your Pocket PC will look exactly like an Apple iPhone.

Free Image Hosting at allyoucanupload.com

Make sure you visit this thread for more details.

Update:

Here’s another fully featured iPhone skin at >Modaco which includes:

Homescreen
RJ Shortcut Plugin
Extra screens
Bootup and Shutdown Screens
Windows Media Player skin
Ringtones
Keypress tones
Automatic CAB installer for easy installation

This skin is specifically made for Windows Mobile 5 QVGA mobile devices.