Be careful of the journals run by Bentham Science, where you pay to get a paper in. They claim to be peer-reviewed - but one of them accepted a paper consisting of computer-generated random sentences, whose imaginary authors both worked at the Center for Research in Applied Phrenology (CRAP).

Other open access journals can be good! I recently published a paper in Entropy, and there were two referee reports, both by people who read it carefully and suggested improvements.

Here are the Bentham Science journals:

http://www.benthamscience.com/open/a-z.htm

It's possible that some are really refereed - I have no idea.

Thanks to +Mark Hahnel for pointing this out!