WordPress ''pop-up'' window

[login to view URL] I need to add a "pop-up" window that comes up the first time a person hits the home page. In that "window" I want to ask people to voluntarily provide their e-mail address (sign up for my e-newsletter). They don't have to. They can either provide their address and it sends me an e-mail or close out the window and then not see it again while on my site. I'm assuming there is a good plugin for that sort of thing, just don't have time to research myself.