Specs
5 WebSphere 5 has basic JMX support
6 WebSphere 6 has further JMX support in the form of JSR-77 support and JMX 1.2. It seems to incorporate MX4J 2.0.1 as its JMX implementation.
It properly supports the ManagementHome access of JSR-77, but doesn't have that much in the way of statistics and state manageable mbeans.
Connecting
MC4J supports WebSphere 5 and 6 connections. The 1.2 beta 7 release had a bug that made all WebSphere support not work, but it is corrected in the next release.
Dashboards
None yet.