OK, not to be nit-picky (but doing it any way...) a snowflake has 6 sides, not 8. The sample is really lovely, but doesn't look like a snowflake to me....
Here's a link to a free paper pieced version:
http://www.quiltmaker.com/webextras/...t79/index.html
See, six sides!
you can resize the pattern to whatever size you need, but since it's a hexagon and it sounds like you are looking for a square you would need to add fabric to square it up.