It seems to be an age old question; "What color will the pups be, if I breed my brown dog with a black dog?"  Here are some articles that will help answer these questions.  Be careful, some of these are pretty boring..........zzzzzzzzzzzzzzzzzzzzz

http://www.labbies.com/genetics.htm

http://www.blueknightlabs.com/color/coatcolor.html

http://www.lockeonlabradors.com/coat_color.htm