Twitterholic is a site where you can know the Top 100 Twitter users (also available up to Top 1000 users) based on number of followers, friends, updates and the date of joining Twitter.
Its twittastic robots can scan the Twitter public timeline for new twits to tweet.
A few times a day, it calculate individual statistics for each twittering twit in its database.
In other words..It’s IN UR TWTTR PAGES, READN UR STATZ
If you deserve to be on the list, it’ll find you.
This list is being constantly updated so you can find out who the most popular twitter users are. The most popular users on twitter are crawled every day, everyone else gets crawled randomly.

Twitterholic Website