If you own a BlackBerry phone, then you can create your own themes using Theme Studio from BlackBerry. BlackBerry Theme Studio allows you to design and make your own themes for your BlackBerry. There are two applications included in BlackBerry Theme Studio. The first, Composer, is an editor for creating interactive, animated graphics for your display and the second, Theme Builder, lets you make themes by customizing elements of the BlackBerry user interface.

You can download theme studio from here.