Laptop ram is laptop ram, mac or no mac. You need the right memory numbers, but if you take the old ram and take it to a futureshop, bestbuy, staples or even a mom and pop shop like the one in the Food Basics place you can get a ram upgrade for a lot less then you will pay at the apple store.
http://docs.info.apple.com/article.html?artnum=303721
Gives instructions for how to upgrade your ram, if that isn't the right model macbook, you can search apple help from that page for the right one.
I love visiting the mac store, but I will be the first to tell you it can be an expensive trip, so if you are confident in your abilities you can do it yourself pretty easy.
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14C - Lot 82 - Upland B
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