I saw some posts a while back, people were asking how to do this. I thought I would share with everyone.
create a new Run/Debug Configuration
main class: org.jboss.main
(it won't be on the selector, just type it in)
(change the above to reflect your locations)
(once again, change the above to reflect your location)
save that, then click the debug icon up top.. your server should start in debug mode and spit output to the IDEA console. (very nice)
Now you can start your program in debug mode and server side debug. If you want to trace into any JBoss source code you will need to setup the JBoss source code in your program source path.
If you experience slow debug stepping, then make sure that you are running IDEA and your targets in the same JDK. Also be sure to click "Force classic VM" in the debugger options. This give you faster debugging. For this reason we still develop using 1.3 jdk, since IDEA 2.6 only runs in 1.3.