So there is loads of sheep out there 🙂 well fire sheep, to be precise open wirless points, with out wpa and un secured. So there is some lovely session hacking out there to be done.
The reg gives nice article on this below
http://www.theregister.co.uk/2010/11/04/firesheep_theatre/
And if your looking for the plugin to do a bit of firesheep’ing a good google, should find it for you in seconds!!!