user15736 Really answered the basic principle behind your question fairly well. Diet is the key part to any change in physical fitness (gaining weight or losing weight).
But I took a quick look at both programs, and I have to say I would go with
Lee Labrada's online 12 week program
Home training is ideal in terms of efficiency, but lack of equipment and proper space can mean less of a "workout" and prolong the time it would take to reach the same goal.
In Lee Labrada's online 12 week program The workouts are formulated by grouping certain muscles with a good amount of high rep (10-12) weight training to burn fat and tone down, with cardio in between days.
Using external weights as opposed to just body-weight is what can give you a bigger advantage when training (excluding cardio days). That is why I would personally choose Lee Labrada's online 12 week program versus P90x. Although I'd even go as far as saying you should add a good 20 minutes of cardio to certain weight training days if you really want to burn off fat quicker.