Any normal 6GB kit will be 3 sticks. Triple Channel does not function on Sandybridge which means using 3 sticks will limit you to SINGLE CHANNEL mode. I guess you could do a 2x2GB Kit and a 2x1GB Kit to make 6GB if you wanted though.
LGA 1155 is Dual Channel
LGA 1156 is Dual Channel
LGA 1366 is Triple Channel
Dual Channel: 2 Sticks per Channel with 2 Channels per board equating to 4 sticks Total.
Triple Channel: 3 Sticks per Channel with 1-2 Channels per board equating to either 3 or 6 sticks Total.