These are the press release submission services that we have used to submit press releases. These are basically free services, but you can pay $10 or more to get a better placement in the search engines.
https://secure.dataovation.com/prweb/login.php
http://www.24-7pressrelease.com
http://www.free-press-release.com/
http://www.click2newsites.com/press.htm
http://www.webwire.com/LoginPR.asp
http://www.mediasyndicate.com/
Article submission sites: