Monitoring Postgresql performance

Hi all,

   I have been "googling" a bit searching info about a way to monitor
postgresql (CPU & Memory, num processes, ... ) and I haven't found
anything relevant. I'm using munin to monitor others parameters of my
servers and I'd like to include postgresql or have a similar tool. Any
of you is using anything like that? all kind of hints are welcome :-)

Cheers!
--
Arnau