I just bought a new MacBook Pro, and I'm wanting to upgrade my memory from 2GB to 4GB (I read somewhere these new machines can add up to 8GB, but only recognize 4GB?). So, my question(s) is, what type do I need, what brand should I buy and where's the cheapest to buy it? I'm a brand new Mac owner and have never been the most computer savvy anyway, so pardon my ignorance.