In this tutorial I created a button that contains the picture of a certain user and has the name of the user below. You can compare it with the login screen of Windows Vista. The purpose of the tutorial is to break the template of a control and rebuild it just the way you want. The only tool I use in this tutorial is Expression Blend. You can download a PDF document that describes the different steps or you can also download the video that shows how the button is created.
More tutorials can be found on my blog: http://wpf-tutorials.livejournal.com