Clustering

I haven't found any information on clustering with PostgreSQL.

One idea we've been tossing around is through PostgreSQL you can
create a function that does something when something else happens.

Pseudo code:
When databse xyz table companyname is updated update the same table
and rows in database abc;

So each time an update is made, the server performs the function. So
every update is essentially 1xN updates (N is the number of servers),
but is all done at the server level so should be fast.

Now the problem with that solution is if a server db/table gets
updated and when it is sending that same update over the net to the
offsite cluster, the server crashes. That update technically went
through, however the record of it is lost.

What is a good clustering technique for PostgreSQL?

~PatHaugen