Watch the Mixing Major & Minor Blues online guitar lesson by Fareed Haque from Soul Jazz Survival Guide
Now this is where it starts to get fun. If the C major blues scale gives you all of the sweet notes in C major, the C minor blues scale gives you the funky sounds. So, anywhere you have C major, try adding in C minor pentatonic licks. Similarly (and this can start to get confusing, so try not to think about it, but just look at it on the guitar neck...it'll make more sense that way) the A minor blues scale will give you lots of funky sounds, if you want to add in some sweet sounds, throw in some of the notes from the A major (F# minor) blues scale.