Amazon.com: OWC 4GB PC5300 DDR2 667MHz SO-DIMM Memory Compatible with MacBook (Late 2007/Early 2008), MacBook Pro (Mid/Late 2007, Early 2008), & iMac (Late 2007) Systems with Core 2 Duo Processor : Everything Else
A-Tech for Apple 6GB Kit (1x2GB + 1x4GB) DDR2 667MHz PC2-5300 200-pin SODIMM for MacBook (Late 2007, Early 2008, Early 2009), MacBook Pro (Mid 2007, Early 2008), iMac (Mid 2007) - Memory RAM Upgrade at Amazon.com
MacBook Pro 15" Unibody Late 2008 and Early 2009 RAM Replacement - iFixit Repair Guide