Monitoring streaming replication lag

Once you've set up the great new Streaming Replication with Hot Standby in PostgreSQL 9.0, you need to somehow monitor it. I've created a simple Munin plugin to graph the lag between the master and the slave, and also the lag between receiving and applying on the slave. It's available on my github page, and will likely also be included in the next Munin version. If you are using SR and Munin (or just SR and want to graph it), please try it out and let me know if there are issues with it - it could certainly do with some more testing.