iMac 2.4 GHz (24-inch, Mid 2007) — Keane Mac Repair
MemoryMasters 6GB (4GB + 2GB Memory Upgrade Kit) Memory RAM for Apple iMac 2007 7,1 at Amazon.com
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-inch Mid 2007 Core 2 Duo Processor 2.4 GHz 250GB HDD 3GB RAM | eBay
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
iMac (2007-2009) Memory Installation Video - YouTube