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Okay, Okay... So you're wondering what "Take it to the mattresses" means? Well, my friend, you're in luck. I'll give you the quick and dirty answer to the question. The simple Cliff note version is "go to war". That's it. So if you've seen "You've Got Mail", Kathleen (Meg Ryan) is going to take it to the mattresses with the big bookstore. She is going to fight (or go to war with) the bigger bookstore. It is usually an all out battle that will have one side victorious over the other.

So where did this quote originate. I'm not sure, but I first heard it from "The Godfather".

So the next question should be, what's the deal with mattresses? In the movie, one family decides to attack the other family. This creates this massive bloodbath with many people dead on both sides. Since there is strength in numbers, the gang members pick a location and stay together. They rent "mattresses" for all the guys to sleep on while they are holed up together. This indicates that it will be a long drawn out war between the two families.

So now you know the explanation of the quote. The Godfather has so many good quotes. "Monday, Tuesday, Thursday, Wednesday", "I'm gonna make him an offer he can't refuse", and "Leave the gun, take the cannoli".