Here is a nice collection of some awesome photoshop & vector Twitter tutorials. These tutorials include character tutorials, widget & background tutorials.

1. How to Create a Cute and Adorable Twitter Icon in Photoshop


2.  Create a Cheerful Twitter Bird in Photoshop


3. Twitter Background Design How-To and Best Practices


4.  Design & Code: Recent Tweets Widget


5.  Create an Elegant/Grunge Twitter Button


6.  Twitter Background Design: Inspiration and Tutorial

7.  How to create a simple new Twitter Background in Photoshop

8.  Twitter Box User Interface Design in Photoshop


9.  Create a Cute Twitter Bird Icon in Photoshop

10.  Twitter Background Design – Great Tips and Gorgeous Examples


11.  How to Create a One-of-a-Kind Twitter Background in Photoshop


12.  Photoshop Tutorial: Design a Custom Twitter Page


13.  How to Create a Quirky Twitter Bird in Corel Draw

14.  Create a Twitter Style Bird Mascot


15.  Create A Vector Art Twitter Bird Character Icon In Adobe Illustrator


16. How To Make a Unique Website For Your Twitter Updates


17. Creating a ‘Twitteresque’ Bird Vector in Photoshop

18.  Twitter Background using Adobe Illustrator


19. Tutorial: Create A Custom Twitter Icon in Adobe Illustrator CS4


20.  Starfield Tileable Twitter Background Tutorial


21. How to create a nice Twitter icon using Illustrator and Photoshop