Author Exposed is a simple Wordpress plugin that allows your visitors easy and elegant way to see more details about the post author.
This plugin does the same thing as the_author() tag only this time it’s linked to hidden layer (div). By clicking on the author link the layer pop’s up with author info gathered from the profile page, plus gravatar photo, if author email is assigned with one.
Demo : http://colorlightstudio.com/2008/03/14/wordpress-plugin-author-exposed/
Pricing : free