A couple of good articles on the topic.

http://www.bodybuilding.com/fun/luis14.htm

http://www.bodybuilding.com/fun/ss11.htm

I personally have good results conditioning 3 days per week.

Right now I am in phase I of my conditioning.

On Tuesday I run a mile followed by doing 4-6 three minute drills in which I sprint up a 60 meter hill, do 15 plyo pushups, 15 star jumps, backpedal 50 yards, 15 burpees, shuffle 30 yards left, sprint 30 yards right, shuffle 30 yards right, sprint 30 yards left, bound 50 yards ahead, 20 squat jumps, 20 lateral jumps and 15 plyo pushups all in succession without rest. 1 minute between sets. When I'm doing I jog another mile

On Thursday I run 3-5 miles at a nice easy pace and maybe do some rounds of beating the hell out of a tire with a sledgehammer.

On Saturday I basically repeat Tuesdays workout.

My goal is to condition without destroying my fast twitch tendencies, which are quick to go on a high volume running program. When I can do intense 3 minute drills with 1 minutes rest and start each round with a heart rate of 110-120 I know I'm good to go.

On MON, WED, and FRI I'll also do some skipping and quite a bit of lifting.

Keep in mind the most specific form of conditioning is actual sparring. Conditioning is largely specific to the activity which means you might be able to run your butt off and do all this and that and still get thrown in the ring and be out of gas after the first minute if you don't work enough at it.