memory - How much more RAM can I add to my Mid 2007 24" iMac? - Ask Different
iMac 20-inch (Mid-2007) Core 2 Duo 2.4GHz - HDD 250 GB - 4GB | Back Market
How to Upgrade iMac RAM (20" and 24" Aluminum): EveryMac.com
Install memory in an iMac - Apple Support
Install memory in an iMac - Apple Support
CMS 4GB (2X2GB) DDR2 5300 667MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac (Mid 2007) Pc2-5300 - A37 at Amazon.com
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 1GB DDR2 667MHz PC2-5300 200-pin SODIMM for MacBook, MacBook Pro, iMac, Mac Mini - (Early/Mid/Late 2006, Mid/Late 2007, Early 2008, Early 2009) - Memory RAM Module at Amazon.com