I am sharing an Arduino Twitter Client I wrote for the Dexter Industries WIFI shield. We just posted an updated tutorial here: (WIFI Shield - Dexter Industries)
This example uses the library developed by Dexter Industries http://dexterindustries.com/files/DI_WIFI_LibraryPackage.rar
The code is attached below.
DI_WIFI_LibraryPackage.rar (854 KB)