MLA has just been rewritten and there are significant changes including not using the URL and not underlining. Changes go into effect April 2009 with the release of MLA Handbook for Writers of Research Papers (7th edition). General paper formatting (margins, headings, etc.) and in-text citations will remain the same, but all Works Cited style entries will be different from the 6th edition guidelines.

To see a list of the changes, see http://owl.english.purdue.edu/owl/resource/557/15/