Just like as feedburner’s feed counting style clones are another one killer startup is twittercounter.com. Feedburner only counting rss feed reader’s numbers and where as twitter counter will count your twitter’s followers numbers. If you have 1000 followers, they will automatically track your followers and show you.
And if you like you can embed this little widgets on you site’s sidebar or top of the sites page. Thounsads of people using and enjoying this free service. You you want, you can checkout top 100 twitter followers’ list.