A-Tech for Apple 2GB DDR3 1067MHz / 1066MHz PC3-8500 SODIMM Memory RAM Module for MacBook, MacBook Pro, iMac, Mac Mini - (Late 2008, Early 2009, Mid 2009, Late 2009, Mid 2010) Models at Amazon.com
Install memory in an iMac - Apple Support
Apple iMac 27-inch Late 2009 - 2.8GHz Core i7 Apple RAM Memory | Kingston
Apple iMac 3.0Ghz Core 2 Duo 21.5-Inch (Late-2009) *No HDD/RAM* – MSU Surplus Store