Both of these kits will do the job for you.
8GB G.Skill DDR2 PC2-6400 MQ Series (6-6-6) Dual Channel kit
8GB Mushkin DDR2 PC2-5300 667MHz ECC FB-DIMM CL5 (2x 4GB) Dual Channel kit
http://www.memoryc.com/computermemory/ddr2ram.html?Capacity=8GB&Single_Module_or_Dual_Kit=Dual+kit