jQuery Prettydate Plugin
This plugin, originally written by John Resig, provides clientside date formatting in the style of Twitter’s timeline: “just now”, “5 minutes ago”, “yesterday”, “2 weeks ago”. This release extends John’s original release, providing support for internationalization and improving the API a bit: You can specify the source of the ISO-date, while not having to manually set up an interval to update the date formatting over time.
See the link above for usage details.