Clustering and replication options

I am looking for some information about clustering and replication
options for postgresql.

I am aware of pgcluster, but have been unable to find anyone willing
to share details about actually using it in a production environment.
That's a little disconcerting. Is pgcluster not really ready for full
production use right now?

I really would like to setup a multi-master cluster of databases, and
pgcluster seems just perfect for the task. I will be testing it for
myself in a few weeks.

I was hoping I could solicit some advice, or really any information,
about other possible clustering or replication methods. I know slony-
I is available, and that it is used b the .org registry, I believe,
as well as other places. It seems to be pretty mature as well.
However, I'm concerned about the master to multi-slave model. For
databases with mostly reads and fewer writes, that model seems good.
But, it seems like replication lag, not to mention the added
complexity of splitting read and write operations between two
database connections, could cause problems for applications with a
large number of both reads and writes. Any lag would potentially
allow stale data to be read from a slave after it had been updated on
the master.

Can someone point me at some good references for either slony-I or
pgcluster, other than their actual home pages? I've spent more time
reading and analyzing the pgcluster configuration than slony-I, as my
needs include support for frequent, multiple writes.

Thanks,
Greg