Geographic High-Availability/Replication

Hey all, new postgres user here. We are trying to setup/research an
HA/Replicated solution with Postrgresql between a datacenter in LA and a
d.c. in NY.

We have a private LAN link between the two D.C.'s with a max round-trip
of 150ms.

We will have a web server at each d.c. (among other servers) that will
write/read to/from the local LAN DB. On writes, that data should be
xmited to the other data center so that if, for whatever reason, my
website request was sent to LA instead of NY, all my session information
etc will still exist.

I was looking into PGCluster 1.7rc5 but their website states:

"...running one Cluster DB node in a different geographical location is
not what PGCluster was built for..."

Does anyone have an idea? We cannot possibly be the only company needing
to do this.

Thanks,
Matthew