Table Timemachine!

Guys,

I've been asked by a colleague about methods to keep track of
'previous' contents of a table - i.e. changes made and a way of
getting back to a previous state. Now, I know INSERT/UPDATE/DELETE
triggers to maintain an accompanying table is a way to do this. But, I
have a nagging feeling that somebody has at one point put together
such a feature in a generic fashion... I thought there was a 'time
machine' module in contrib! Searches through the mailing lists have
not turned up any specific pointers.

Aanyone else remember this, and remember where? Or am I misguided and
deluded!

Thanks, Lee.