S.L.
My daughter went to a pajama party breakfast once when she was young.
You could serve cute pancakes and or muffins. this site http://www.ehow.com/how_###-###-####_throw-birthday-pajam... has ideas for favors and a decorate a pillow craft, decorations that are stars and moons. Another idea would be to buy plain white Tshirts in a size 6/8 and let them decorate sleep shirts. Have Fun!
You could decorate the house with a stars and moons theme and decorate a cake something like http://www.marthastewart.com/343304/stars-and-moon-cake