timestamp

Hi!

I am rather new to PostGreSQL, having mainly used MySQL until now.
MySQL has a column type TIMESTAMP[1] which holds - as expected - a timestamp, but additionally this timestamp is being
updatedautomatically on any UPDATE or INSERT operation.
 

Since this is a quite handy feature to keep track of latest changes I would like to create such a behavior for my
PostGrestables too. But since I have no idea how to do it I would warml welcome any suggestion... :)
 

Thx 
dj

[1]
http://www.mysql.com/doc/en/DATETIME.html