There are lots out there - I actually assembled a list of free ones that I found..
http://yarn-or-fabric.weebly.com/sew...r-infants.html
I have not made any of them however if you look through them, you will find one that suits your needs I'm sure :)
This one however would probably do the trick :)
http://feedthedogsnow.blogspot.com/2...-tutorial.html