A-Tech for Apple 6GB Kit (1x2GB + 1x4GB) DDR2 667MHz PC2-5300 200-pin SODIMM for MacBook (Late 2007, Early 2008, Early 2009), MacBook Pro (Mid 2007, Early 2008), iMac (Mid 2007) - Memory RAM Upgrade at Amazon.com
A-Tech for Apple 4GB Kit 2X 2GB PC2-5300 667MHz Mac Mini iMac Late 2006 Late 2008 Mid 2007 A1208 MA589LL A1207 MA456LL A1200 MB138LL/A A1176 MB139LL/A Memory RAM at Amazon.com
Install memory in an iMac - Apple Support
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Memory Upgrades for Apple iMac 2007 - Up to 6GB
CMS 4GB (2X2GB) DDR2 5300 667MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac (Mid 2007) Pc2-5300 - A37 at Amazon.com
Apple iMac 20" Mid 2007 Core 2 Duo 2.0GHz 2GB RAM 250GB HDD Radeon HD 2400 XT | Being Patient
4Gb (2X2Gb) Memory RAM Compatible with Apple Imac (Mid 2007) Pc2-5300 By CMS (A37) - Computer Memory Solutions
iMac (2007-2009) Memory Installation Video - YouTube
6GB Memory for 2007-2008 MacBook Pro, MacBook, and iMac