Kingston Apple 4GB Kit 667MHz DDR2 SoDimm Dual Channel Memory (KTA-MB667K2/4GR)

Kingston Apple 4GB Kit 667MHz DDR2 SoDimm Dual Channel Memory (KTA-MB667K2/4GR)
Customer Review: Works perfectly in my MacBook Pro

Bought this RAM for my Core2Duo MacBook Pro and it works perfectly. Easy to install, you just need a tiny jeweler's style screwdriver and much, much cheaper than Apple's ridiculous price.
I don't understand why Steve Jobs needs to sell machines with two RAM slots using 2x1GB chips, especially when he wants Apple to be seen as "environmentally friendly." Nobody savvy is going to pay Apple's RAM upgrade extortion prices, so why not offer a 1x2GB option for extra, leaving one RAM slot free, so the customer can buy a single, additional 1x2GB chip elsewhere? Apple gets extra money from the 1x2GB fee, the single additional chip is cheaper for the end user and it saves two 1x1GB chips from going in the garbage.

Customer Review: great update for my penryn macbook

I bought this ram upgrade for my penryn macbook and I've been very pleased with its performance. My computer seems to load a little faster, as well as improving the speed at which it manages multiple programs running at the same time.
This is a much less expensive option compared to buying the ram through apple. Installation is easy as long as you have the right tool (small screwdriver) and you can even watch tutorial videos on the apple website or youtube.