Check out this article from Forbes: http://www.forbes.com/sites/andygre...elaborate-jailbreak-to-ever-hack-your-iphone/
It was pretty interesting reading (though most of it goes over my head - I'm a jail break user, not a coder! ).
There are other articles out there describing what the evad3r team did - this was just one of the first ones I found in my search.
Marilyn