Java-monitor.com has released a new, free Openfire plugin that allows you to monitor your Openfire instance remotely. The plugin will notify you if your server goes off-line. It also allows you to keep a close eye on a number of important health indicators, such as the usage pattern of the Openfire worker threads, JVM memory usage and garbage collection statistics, JVM thread and Openfire's database connection pool usage.
Unlike most monitoring tools, you don't have to set up a monitoring server yourself for this to work. Java-monitor.com provides the infrastructure to do the monitoring for you. The probe that's integrated in the Openfire plugin sends statistics to java-monitor.com. Everything else is handled there. You can view the data from their website, as shown below.