Google states you can't set up a naked domain with Google Sites. I found you can and I'll tell you how.
First, a naked domain is when someone enters as a URL, just the domain (e.g. blueoakdb.com) and you'd like it to map to www.blueoakdb.com
While it's true you cannot set up an @ CNAME record, you can set up a Web Forwarder using an @. By so doing, you emulate a naked domain. :)
Test it out, http://blueoakdb.com goes to http://www.blueoakdb.com