OWC 8GB RAM Kit (2x4GB) iMac Early 2009 - Late 2009 - 4mac
Buy Timetec 16GB KIT2x8GB Compatible for Apple DDR3 1067MHz 1066MHz PC3-8500 RAM for Mac Book Mid 2010 13-inch, Mac Book Pro Mid 2010 13-inch, iMac Late 2009 27-inch, Mac Mini Mid 2010
Install memory in an iMac - Apple Support
memory - Will this RAM work for me? (Late 2009 iMac) - Ask Different
2009 iMac (Late) - 1066MHz – SimplyMac SG
Apple iMac 27-inch Late 2009 - 2.8GHz Core i7 Desktop DDR3 RAM Memory | Kingston
Review: Apple's 27" big screen iMac (late 2009) | AppleInsider