Yeah a great exercise for sure ! I feel it in my middle chest, and few exercises target that area in this matter.

Ryan my chest was exactly this shape in the lower portion. All I did was make sure I was getting 100% even muscle stimulation in both the right and left pec and the shape actually changed slightly and now they look pretty even. I believe even stimulation is more important than doing isolation exercises. Let me know if this helps.

Hey Daniel

Thanks for the help.. What would be some good workouts for even stimulation to improve my chest?? :)

Hey man, I remember doing a post on this a while ago, here you have it:
http://scotthermanfitness.com/forums.php?pageAction=POSTS&subForumID=32&threadID=155

Chest stimulation begins with you being able to actually feel the muscle working. I started off just flexing the pecs in a mirror and making sure I felt both parts of the pec working evenly and that they looked symetrically flexed. The exercise I then used to activate the pecs was the bench press. A lot of people will say this exercise will not stimulate the chest like other exercises but that is because they are not using the pecs to move the bar. When you are benching you must retract and depress your shoulders whilst maintaining an arch in your lumbar spine (I'm sure Scott has gone into greater detail about this in his videos). In order to stimulate the pecs you must think about bringing your hands together, squeezing the pecs to do this. The next important thing is tempo. Select a light(ish) weight and do a 1-1-3 tempo. I guarantee this will burn out the pecs and allow to you to stimulate them as much as possible. For example since I have been doing this technique I have literally been able to fatigue my chest very quickly as I have learned to primarily use the pecs to create motion. Try this technique and let me know how you get on.