OWC 6GB (2GB + 4GB) PC8500 DDR3 1066MHz SO-DIMMs Memory Compatible with Late 2008, Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, 2009/2010 Mac Mini, 2009 iMac Models at Amazon.com
Install memory in an iMac - Apple Support
8GB kit (2x4GB) DDR3 1066 SODIMM for Apple iMac (2009), MacBook Pro (2 – Aplus Technology
8GB Kit (4GBX2) DDR3-1067Mhz for Early/Late 2009 iMac and 2009-2010 MacBook Pro at Amazon.com
How to Upgrade Mac Pro Memory (Early 2009/MacPro4,1): EveryMac.com
iMac Intel 20" Early 2009 EMC 2266 - used original spareparts for Macs
8GB -2x4GB Memory Ram Upgrade 20" Apple iMac 9.1 2.66GHz Core 2 Duo Early 2009 | eBay
iMac | 3.06 GHz Core 2 Duo | 24 Inch | Early 2009 - Techable.com
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
how to upgrade iMac early 2009 SSD and RAM - full class - YouTube
Early 2009 model iMac Computer, DDR3 8GB (2x4GB) RAM Replacement - YouTube
iMac 24-inch (Early 2009) Core 2 Duo 2.66GHz - HDD 640 GB - 4GB | Back Market