I still stand by my opinion. I must totally contradict the impression one can grow his biceps well through chins/pullups.
I can do lots of this exercise and my biceps sucks ass. I incorporated direct biceps work only recently and voila! It grows. Same with lots of sportsbuddies. The able chinners tend to have better definition and impressive veins, but that's about all what is impressive about their arms.
Nontheless, the best chin to target the biceps is the following:
With hands about shoulderwide, palms supinated, chin yourself up
Do two or three reps to warm yourself up. It's gonna be hard
Tempo is about 2 for the positive part, 1 second for the isometric part and 3 seconds for the negative
Now start to chin your chin over one hand, alternating hands with each rep
Hold it there for two or three seconds using only minimal strength from the other arm
If you're good enough: As you hold yourself up in the isometric part, slowly remove the "lazy" arm and lower yourself with only one arm as slow as you can.
for the negative part, your body must be very close to your hand.
Final note:Don't do these every day, since you won't make any progress