Go to hornetq trunk and there is a README.
Maven support has been improved a lot in Eclipse 3.7 "Indigo", you
really should use it. There are still some Maven plugins used by
documentation sub-projects which are not supported even in Eclipse 3.7.
The M2Eclipse plugin only works correctly with javacc Maven rules in
Eclipse 3.7. So in Eclipse 3.6 you need install M2Eclipse yourself, and
after importing the projects you should use "Maven / Update project
configuration" to fix up the projects."
It would be great to have a small introduction on how to run hornetq in standalone mode (eclipse), configure cp, etc ... this way one would spend less time trying to figure out how to start.