Google SEO - does it consider a domain with a www and one without as two separate sites?

Question

A friend of mine had a report done on an old site I built. One of the issues mentioned in the report was the following:

Your website needs a www resolve. Currently you can go to http://urmarialarts.com or http://www.urmartialarts.com which means in Google's eyes you have two websites with the same content. You should set the hosting up so you are redirected

Is this the case? And if so do I need to setup a 301 redirect on one of the domains to point to the other?

Answer 1

Yes and yes, for further information: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=44231