There are tons of tutorials about how to setup streaming replication on postgresql 9.0, and detailed documentation on repmgr, the SR manager program from 2ndQuadrant. Like they said on repmgr homepage:
“PostgreSQL 9.0 allow you to have replicated hot standby servers which you can query and/or use for high availability. While the main components of the feature are included with PostgreSQL, the user is expected to manage the high availability parts. repmgr allows you to monitor and manage your replicated PostgreSQL databases as a single cluster.”Mas:

http://www.howtoforge.com/how-to-set-up-a-postgresql-9.0-hot-standby-streaming-replication-server-with-repmgr-on-opensuse-11.4