How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
OWC 2GB PC8500 DDR3 1066MHz SO-DIMM Memory Compatible with Late 2008, Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, Late 2009 MacBook, 2009/2010 Mac Mini, & 2009 iMac at Amazon.com
Memory upgrade to 8GB on unibody MacBook - Super User