4GB [2x2GB] DDR2-667 (PC2-5300) RAM Memory Upgrade Kit for The Apple iMac 7,1 (20-inch, 2.0GHz, MA876LL/A) Intel Core 2 Duo (Genuine A-Tech Brand) at Amazon.com
Amazon.com: OWC 4GB (2 x 2GB) PC5300 DDR2 667MHz SO-DIMMs Memory Compatible with MacBook, MacBook Pro, iMac, Mac Mini Core 2 Duo Models (OWC5300DDR2S4GP) : Everything Else
Crucial 4GB DDR2-667MHz (PC2-5300) CL5 ECC RDIMM DR 240-pin Server Memory CT51272AB667 at Amazon.com
Kingston ValueRAM 2GB DDR2 667MHz FBDIMM Desktop Server Memory at Amazon.com