There are a lot of ways to skin Windows Mobile. Chief among them is by using Wisebar Advanced Desktop 2 (WAD2), which goes a bit deeper than some of the alternatives.
In this video we show you a particularly cool Windows 7 skin for Windows Mobile that uses WAD2. It utilizes many real aspects of Windows 7 such as the start menu, taskbar, My Computer, system tray, desktop icons, and media player (not shown).
That said, it’s not easy to install. Unless you consider yourself a strong intermediate or solid advanced user, I wouldn’t try it, as it requires almost a dozen steps to get going. But if you’re brave, head over to the thread at XDA where user rajivshahi gives you all the info needed to install the skin (you’ll want to grab the installation guide). Right now, it will only work on QVGA and VGA device.