Melamine in food is toxic. Melamine resin is made from the chemical melamine and some other chemicals, but it is not toxic to eat off of. It's not actually correct to call melamine resin simply melamine.
Many plastic things are made out of it, including laminate floor tiles, etc.
I don't think it's too toxic for us! (Just like chocolate, etc. is not toxic for us, but it is for dogs)