There are quite a few online periodicals about philosophy. Most, however, charge a subscription fee or a fee per article in order to view and download the complete article.
This is a list of titles available for searching if you are willing to pay for their service. Also note that some of these titles can be found in the local list or in the ProQuest list (both on the left) which do not require payment. If you are interested in these online titles, however, google the title to gain access.
American Philosophical Quarterly
Journal of Ethics
Journal of Philosophy
Pacific Philosophical Quarterly
Philosophy and Phenomenological Research