Free pattern from Heather Ross.
From Heather Ross:
This is my most favorite summer dress: simple, chic, comfy, lovely. I have had students (at Purl Patchwork) of every shape and size make and wear this dress, it truly works on everybody. The bodice features super stretchy elasticized smocking, a trick anyone with a home-sewing machine and elastic thread (first thing to know: you put the elastic thread in your bobbin, NOT your needle thread!) can master. My instructions include a few pointers, and you can also find useful tips here. The skirt is nice and full and can be hemmed at a variety of lengths, and features two hidden on-seam pockets.