Yes, provided that the ram is 1.5v supported ddr3. Beware of anything over 1.65v.
Triple channel kits will usually contain three sticks, that gives you triple channel capability on X58 chipset motherboards.
On a P67 motherboard you can only have two channels. The first two sticks will operate in dual channel mode, and the odd stick will operate in single channel mode.
It might be a performance hit of 1-2%; but the extra ram more than makes up for it.