Use a Bitmap to Create a Skinnable Irregular-Shaped Form
Some applications (such as the MP3 players Sonique and kjofol) allow you to use non-rectangular bitmaps with transparent sections.
The following demo does just that. I'm no graphics artist, though, so to create a better-looking skin you'll have to work hard - but the code is here for you to do it.
Note that you can move the form by pressing and dragging the mouse anywhere on the form - even though it doesn't have a title bar.
Instructions: Click the link below to download the code. Select 'Save' from the IE popup dialog. Once downloaded, open the .zip file from your local drive using WinZip or a comparable program to view the contents.