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 20" mid 2007 w el Capitain, 6GB Ram, 320GB HDD /READY TO GO../good working! | eBay
CMS 4GB (2X2GB) DDR2 5300 667MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac (Mid 2007) Pc2-5300 - A37 at Amazon.com
iMac Memory Upgrade (2007 Model) - YouTube
iMac (2007-2009) Memory Installation Video - YouTube