How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
How to Upgrade iMac RAM (20" and 24" Aluminum): EveryMac.com
iMac (2007-2009) Memory Installation Video - YouTube
iMac (2009) RAM & Storage Upgrades
2GB Team High Performance Memory RAM Upgrade Single Stick For iMac “Core 2 Duo” 2.93 24-Inch (Early 2009) MB419LL/A iMac 9,1. The Memory Kit comes with Life Time Warranty. at Amazon.com
How to replace HDD/SSD in iMac Mid 2007/Early 2008/Early 2009/Mid 2009 | Mac Cheat Sheet
Install memory in an iMac - Apple Support
Install memory in an iMac - Apple Support
Memory Upgrades for Apple iMac 2011 Up to 32GB
Apple iMac 24-inch, Early 2009 - 2.66GHz Core 2 Duo Memory RAM Upgrades - Low Cost Delivery & Guaranteed Compatible | Mr Memory®