Facebook share plug-in for WordPress which shows the number of times the post or page has been shared through out the Facebook just like tweetmeme button does for twitter.
Facebook has just released this new share button and you might have seen this on http://Mashable.com as they were one of the lucky Beta testers of Facebook share.
* New - Facebook Share button which also shows count
* Integrates the ability to share your post with one click
* Shows the current number of times your post has been shared on Facebook
* Analyze share counts, like counts, click counts, comment counts for your post across the Facebook.
* Easily installation
* Allows you to specify when the button should go (e.g. top or bottom)
* Show it on Post or Page or Both
You can see more information here: