Amazon.com: OWC 4GB PC5300 DDR2 667MHz SO-DIMM Memory Compatible with MacBook (Late 2007/Early 2008), MacBook Pro (Mid/Late 2007, Early 2008), & iMac (Late 2007) Systems with Core 2 Duo Processor : Everything Else
Install memory in an iMac - Apple Support
2007 Apple iMac 2.4 GHz Core 2 Duo 24-inch 4 GB RAM 2 TB - Office + Yosemite | eBay
Apple iMac A1224 20" Core 2 Duo 2.4GHz 1GB RAM 320GB HDD No OS | eBay
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
iMac 2.4 GHz (24-inch, Mid 2007) — Keane Mac Repair
Apple iMac 24-inch Mid 2007 2.4GHz Intel Core 2 Duo (MA878LL) – UNICOM, Inc.
Memory Upgrades for Apple iMac 2007 - Up to 6GB
iMAC 24" Mid 2007 Intel Core 2 Duo 2.8GHz 4GB Ram 500 HD Radeon 2600 (A1225) | eBay
4GB NEMIX RAM Memory for Apple Module iMac 2007 System Specific Memory - Newegg.com
iMac Memory Upgrade (2007 Model) - YouTube
6GB Memory for 2007-2008 MacBook Pro, MacBook, and iMac
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
4GB 2 X 2GB DDR2 Memory for iMac 7,1 Mid 2007 20" inch 24" inch Intel Core 2 Duo 2.4GHz PC2-5300 667MHz 200 pin SODIMM (PARTS-QUICK) at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Install memory in an iMac - Apple Support
iMac (2007-2009) Memory Installation Video - YouTube
How to replace HDD/SSD in iMac Mid 2007/Early 2008/Early 2009/Mid 2009 | Mac Cheat Sheet