This site has it all! Loads of crochet stitches plus knit, tatting, lace making and much more! This stitch is called Crossed trebles. The site this comes from is full of wonderful stitches, tips and tricks. It's certainly worth a look around.
This is an easy pattern. Circles are easy to crochet in general in simple dc, sc, etc.: just keep increasing groupings one more stitch farther apart for each and every new row and the circle should lay flat even if you keep going like that for forever.