a cute idea would be to have everyone bring one children's book to start the baby on her book collection. everyone could write a nice little note on the inside under the "this book belongs to..." another cute idea would be to buy plain white onesies and some fabric markers and have each guest design a cute, creative onesie for the baby. or everyone can write a short little paragraph on a sheet of pretty stationary about the mom-to-be. they can write nice things about the mom-to-be like how great/fun she is, what kind of person she is, and how and in what ways they think she will make a great mother. it doesnt have to be a novel or anything. and then you can put them into a little book to give to the baby and she can read how great his or her mom is when they are older. there are also all kinds of cute/fun games to play at the shower too.
good luck! :)