Yes there is. There is a current working solution for real time mirroring in Postgres. Note that this is a commercial solution. You would need to work with PostgreSQL Inc. to get it:
There are also several non commerical solutions, but they are quite difficult to setup, or are not full real time. Off the top of my head:
There is also a "close to real time" solution as designed by Dr. Carter, that uses Heartbeat and rsync:
There is also a tool called, "dbmirror" in the postgres source tree, under /contrib, but I have no experience with this and I think it is not real time mirroring.
The main userland replication tool is under development, but is not fully ready:
Postgres replication is fully possible, but will take some work to get it going, it won't be seamless like a commerical product like SQLServer or Oracle.
One thing that you might find interesting, is that the .INFO registry runs on a Postgres replicated database, and the .ORG registry is moving to a Postgres replicated database.