Xbox 360 Gun Controller for Shooters

[Bluefrogs]

Is there a gun controller available for the Xbox 360 that you could use with shooter games? Up until now, I've never really played shooters, other than occasionally playing Call of Duty here and there, but I think I would really like shooters if I actually had a gun-style controller to use. Does such a thing exist, and is the technology well-developed enough to make it fun?