MemoryMasters 6GB (4GB + 2GB Memory Upgrade Kit) Memory RAM for Apple iMac 2007 7,1 at Amazon.com
Install memory in an iMac - Apple Support
New Memory Ram Upgrade 4 Apple iMac 24" Core 2 Duo 2.4GHZ 2.8GHz A1225 MID 2007 | 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
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)