One of the most fascinating aspects of promoting your twitter account is that you don't need to stick to a predesigned logo or badge. The Twitter bird is so widely known that you can design whatever you want, as long as you include a happy singing bird in it. Just let your creativity flow and that's it.
Creating a Cheeful Twitter Bird Icon
Painting Lost Shade Jasmine Tea in Photoshop
Design a Black and White Promotional Mailer on a Budget
How to Create an Illustration that Fades from Line Art to Color
Other Tutorials That Might Catch Your Attention