2GB DDR2-667 (PC2-5300) RAM Memory Upgrade for The Apple iMac 7,1 (20-inch, 2.0GHz, MA876LL/A) Intel Core 2 Duo (Genuine A-Tech Brand) at Amazon.com
Memory Upgrades for Apple iMac 2007 - Up to 6GB
OWC 1GB PC5300 DDR2 667MHz SO-DIMM Memory RAM Upgrade Compatible with MacBook Pro, MacBook, iMac (Intel), and Mac Mini (Intel) Models (OWC5300DDR2S1GB) at Amazon.com
4GB [2x2GB] DDR2-667 (PC2-5300) RAM Memory Upgrade Kit for The Apple iMac 7, 1 (20-inch, 2.0GHz, MA876LL/A) Intel Core 2 Duo (Genuine A-Tech Brand) at Amazon.com
iMac (2007-2009) Memory Installation Video - YouTube
Install memory in an iMac - Apple Support
iMac (2007-2009) Memory Installation Video - YouTube
Memory Upgrades for Apple iMac 2007 - Up to 6GB
How to Upgrade iMac RAM (20" and 24" Aluminum): EveryMac.com