Complete Twitter like follow and unfollow script.

I'm looking for someone who can make a Twitter like follow and unfollow script, configured with PHP and MySQL. It needs to be dynamically, and the user must have the option to unfollow and follow. It should work pretty much like Twitter. It's important for us that it works backwards and forwards; when a user press follow he/she must have the ability to unfollow and follow back again (and so on..) without ever refreshing the website. Also, when the user refreshing the website it's necessary that the button is showing the right button (follow or unfollow.) Can you hit the job?