Designed for bubs with large feet, the back of these slippers is fairly wide. Pattern sized to fit a 3mo, however up or downsize the hook or yarn to achieve other sizes.

Update July 10 2011:
It appears I crochet rather tightly, you may need to swap to a 4.5mm or a 4mm hook.

Swapping to a smaller sized hook to do the final row of slip stitches will pull the slippers in more for a snugger fit.