The best part about them aside from matching, is the cris-crossed cut-out back. Which you can't see in the picture, of course!!! Makes it a little tricky to put on - but adorable!
The dress pattern is Malibu by modkid and can be found here. Simple pattern with great instructions, and made really easy with fold over elastic! I should probably make a few more of these... it's hard to find great knits though.