We have the pack n play, we have the sheets...but I didn't even think about a waterproof cover like we got for the crib. Is this necessary? I saw this on Amazon but many reviews said it was too small to fit the Graco PnPs. Did you use a waterproof PnP mattress pad and if so, what brand worked well for you?

http://www.amazon.com/American-Baby-Company-Waterproof-Portable/dp/B000BPMJR6/ref=sr_1_6?s=baby-products&ie=UTF8&qid=1364773782&sr=1-6&keywords=graco+pack+n+play+waterproof