I've just returned from MicroCenter. If there's one in your area, I highly recommend it. They allowed me to upgrade the RAM myself in store with borrowed tools.
Also I'm not sure if you meant two 2GB sticks or 2GB total - if the later definitely go for 4GB instead, it's worth any cost difference. I'm getting 0 page outs so far and not a beach ball to be seen yet (yeah, probably speaking too soon).