Interestingly enough, Twitter has a large following other than just Tweeters.  There are a ton of free resources for use, graphics, inteface etc.  Thought I'd share some:

• TweetLister.com - A free olnine Real Estate listing service tied to Twitter which also allows to to schedule automatic tweets of your listing over a period of time. 
• JustTweetit.com - A great online resource for all thins Twitter including graphics, directory, and much more.
• Books - Yes, people have written a ton of books on just Twitter.  Click here for a list and order from Barnes & Noble.
• Twitter Graphics by Randa Clay Design.  'Follow Me' buttons, insight, and more.
• TweetDeck - Great standalone application that is free and provides for column views of tweets, direct messages, etc. all on one screen.  Plus it adds features to shorten URL's right underneath the Tweet box rather than having to go to another site like www.TinyUrl.com
• Tweet Pictures with TwitPic - Great site to upod pics and it creates a little URL to Tweet.
• Search Twitter - Great site to search for Tweets and Tweeters pertiaing to specific topics such as Real Estate. 
• Celebrity Tweet - Find Celebrities using Twitter
• Twitter Status - Having issues, find out if there is an outage or issues with the service.
• Twitter Rank - We all like rankings.  Find out where you rank on Twitter.  My rank is . . . um . . . '0'.  This isn't that great of a site and obviously has it's issues with accuracy but it's an interesting novelty thing. 
• Twitter Grader - Similar to the site above and on this one I rank 147,000 out of 2M.  Much better site obviously. 
• Twitter Value - So how much are you 'worth' on Twitter?  Find out.  I'm apparently worth $136.  Location Location Loaction!!!!
• Widgets -
  • From Twitter which includes HTML for adding into other websites but also easy ways to add the Twitter widget to other sites such as Facebook
  • From Widgetbox for adding onto websites and blogs

And there is a ton more.  Kind of crazy, but fun as well.