Full Details on Amazon.com : http://www.amazon.com/gp/product/B0091L62V0?tag=tsukuyomi-20

4GB Upgrade for a Apple MacBook Pro 2.26GHz Intel Core 2 Duo (13-inch DDR3) MB990LL/A Mid-2009

204-pin SODIMM
DDR3-1066
DDR3 PC3-8500 Unbuffered NON-ECC DDR3-1066 15V 512Meg x 64
The only brand of memory upgrade available directly from a DRAM manufacturer tested to meet the most stringent industry specifications
Install it yourself in about 15 minutes The same top-quality memory that the worlds largest computer manufacturers install in the systems they sell