How to Upgrade Memory in a Late 2009 21.5-inch or 27-inch iMac - YouTube
iMac: How to remove or install memory
iMac | 2.66 GHz Core 2 Duo | 20 Inch | Early 2009 - Techable.com
DDR3 RAM for Late 2009 iMac | MacRumors Forums
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 21.5" Core 2 Duo Late 2009 3.06GHz 4GB RAM 500GB HDD | eBay
Install memory in an iMac - Apple Support
8GB 2X4GB RAM Memory for Apple iMac "Core 2 Duo" 3.06 27-Inch Late 2009 A35 | eBay
8GB Kit (2 x 4GB) PC3-8500 RAM for Apple iMac Late 2009 - 21.5 Inch BTO/
Apple iMac 24in - 2009 Edition Review | Trusted Reviews
2009 2010 Apple Mac mini IMAC macbook pro memory RAM 8GB 2x4GB DDR3 1066 1067
Apple A1225 24-inch iMac Core 2 Duo 2.4 GHz 2 GB RAM 320 GB HDD Early 2009 | RecycledGoods.com
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com