I spent some time checking out JBoss AS7 today. I am impressed with what I have seen so far but I noticed that good ol\' JMX-Console no longer exist.
There are various web based jmx browsers that can be used inside any web container. I tend to perfect using the jconsole or jrockit mission control as you get extra this like graphing of values
In the past jboss used it's own mbean server, so you could only use jboss specific jmx tools, but now jboss-as, uses the mbean server of the jvm so any tool that works with your jvm of choice can be used for inspecting jboss-as 7