Yes there is a trick to knitting socks on circular needles. I haven't done it yet--I just finished my first pair of socks on dpns and am now researching how to do it on circular needles as I've read it's faster that way--and easier. To get you started on how this is done try this link:
Cat Bordi is one of the first to figure out this method and has a book about it called "Socks Soar on Two Circular Needles". It's got directions and patterns.
I'm sure there are other sources on the Internet too.
Good luck to you.