Kingston KTD-WS667/8G / 8GB (2 x 4GB) - 667MHz DDR2 SDRAM at Amazon.com
AddOn 2GB DDR2 SDRAM Memory Module at Amazon.com
URAM Laptop Memory 2GB 667MHz PC2-5300 PC2-5400 DDR2 SDRAM SODIMM RAM Stick for Mac, Intel, & AMD Systems, blue 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
Amazon.com: HP 454672-001 1.0GB, 667MHz, PC2-5300, DDR2 SDRAM Small Outline Dual In-Line Memory Module (SODIMM) : Electronics