Enterprise pg database monitoring

Hi,

I was interested in finding out how other people are monitoring their postgres database estates.
We use psql and pgAdmin for day to day dba admin tasks, but I was wondering if there were any
good tools available for monitoring such things as whether all of my postgres cluster's were up and
running (similar to oracle enterprise manager dare i say it)? Are people just using shell scripts
scheduled from cron to check such things? This could become an issue if you had 100's of postgres
instances and you need to roll out new monitoring scripts and cron jobs to each...

On the database performance side of things, I've looked at pgFouine which is very useful, and I've
also just found pgStatspack, but are there any other modules, scripts or tools that
you would recommend to help with database administration? They don't necessarilly have to be free either ;-)

Thanks in advance.