Webster's on-line dictionary. Has audio facility. Hear words spoken in AmE
http://www.m-w.com/
BBC learn English site. Has audio in BrEhttp://www.bbc.co.uk/worldservice/learningenglish/index.shtml Randall's basic self-study guide. useful words and phrases in AmE accenthttp://www.esl-lab.com/guide.htm AmE pronunciation (you need Real player for this one)
http://evaeaston.com/pr/a-pattern.html This site says they offer free softwarehttp://www.free-english.com/english/Home.aspx Users should note that http://www.free-english.com/english/Home.aspx is not, strictly speaking, free. You will be required to register and to give personal details such as your address, telephone number, date of birth etc. etc. You will also be required to pay 'shipping fees' on any items you add to your 'shopping cart'. (Thanks to Mike in Japan for this info)
Another talking dictionaryhttp://www.answers.com/main/ntquery?s=dictionary#Dictionary This is a great site for phonectics: animated diagrams to show production of sound, video and audio of certain words.
http://www.uiowa.edu/~acadtech/phonetics/about.html
http://librivox.org/ offers free audio books, and you can be a volunteer to record and add new tiltles to the database.