I just ran across this easy to use application that lets you change your twitter background really easily and for free. It’s run by a group of programmers named Zugara. You can donate some money to them and they send it to the Make a Wish Foundation.
You go to their site FreeTwitterDesigner.com
You sign in using your twitter account if you want it to automatically load your new theme and background automatically. I recommend the twitter sign-in method. It seems to give you more choices in your design.
Or use it without signing in.
Select a theme or use a blank theme.
You can upload an image and it shows you what it will look like in various screen resolution.
You can also change the text colors, link colors background color (if your background image doesn’t cover it all, plus both sidebar colors. The twitter panel can also be ghosted (transparent).
You can add shapes and objects and images and move them around.
It’s fun and easy to use. I highly recommend it!