Memory RAM Upgrade for Apple iMac 21.5-inch Mid 2010 4GB DDR3 SODIMM | eBay
A-Tech 8GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module at Amazon.com
Amazon.com: OWC 6GB (2GB + 4GB) PC8500 DDR3 1066MHz SO-DIMMs Memory Compatible with Late 2008, Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, 2009/2010 Mac Mini, 2009 iMac Models : Everything Else
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 RAM for Mac Book (
A-Tech for Apple 4GB Kit (2X 2GB) DDR3 1067MHz / 1066MHz PC3-8500 SODIMM Memory RAM
Apple iMac 2010 8GB DDR3 1333MHz PC3-10600 204-Pin SoDIMM