Just to burst your bubble a bit, but this has already been done. According to my rather nice book entitled "The Road to the Stars":
"Since February 1973, the Project Daedalus Study Group of the British Interplanetary Society has devoted rather more than 10,000 man-hours to producing a detailed specification of a possible inter-stellar mission utilizing the nuclear pulse rocket. In what is probably the most detailed investigation of its kind, the group has examined all aspects of the mission, from the selection of the target, the specification of the vehicle and its payload, to the question of navigation and communication with the probe throughout the mission."
Admittedly, this project was devloped in 1973, but they had some very very good ideas that are probably still being used today. Since you haven't really discussed it yet, a nuclear pulse rocket basically consists of flinging a large nuclear bomb behind you and exploding it. The force of the explosion hits an abrasive shield, and accordly with Newton's laws, the equal and opposite force propels the spacecraft forward.
So as you can see, there has been rather a lot of thought into this kind of mission.