I just uploaded version 1.3.0 of my WordPress Twitter Widget Pro plugin. It has been updated to allow HTML in the title and error message, which will allow for more inventive titles (like the one currently being used in the sidebar here). Additionally, the plugin no longer relies on you having a caching solution installed and set up. It now caches the tweets for 5 minutes using the built-in blog options functionality. Twitter limits the number of requests you can make in any given hour, so this caching should greatly reduce the number of times you see the “twitter not available” error message. Lastly, we phased out the old Snoopy class in favor of the new HTTP class.
Please discuss this plugin on the WordPress Twitter Widget page.