This is a simple plugin which lets you know in words, roughly how long its been since a post was posted. Its based on the amount of time in seconds since the post was made.
Simply use <? wp_date_in_a_nice_tone(); ?> to display the date in your theme.
The following messages are displayed according to how long its been since the post was made:
A month is assumed to be 31 days (therefore "more than a month" is always accurate, regardless of the month in question, and since from 28 days to 31 days we say "around a month ago", this is also accurate).
A year is assumed to be 366 days (therefore "over a year ago" is always accurate, etc).
See the plugin in action over at ribot.co.uk - we use it in the left hand column




