Crucial 2GB Single DDR2 667MHz (PC2-5300) CL5 SODIMM 200-Pin Notebook Memory Module CT25664AC667 at Amazon.com
Kingston 2 GB (1 x 2 GB) 200-pin 667MHz DDR2 SDRAM at Amazon.com
Amazon.com: OWC 2GB PC5300 DDR2 667MHz SO-DIMM Memory Compatible with MacBook, MacBook Pro, iMac, and Mac Mini Models with Core 2 Duo Processor (OWC5300DDR2S2GB) : Everything Else