I suggest reading these three articles for a little insight into gaining lean weight.
http://www.nutribomb.com/tom_venuto/...lean_body.html
http://www.nutribomb.com/tom_venuto/...an_body_2.html
http://www.nutribomb.com/tom_venuto/...an_body_3.html
Edit:
Btw since you say you have quite a bit of a belly going on there Jim I don't think you should look into gaining weight before you lose it first.