I have released 1.4.1.CR1 for distribution with JBoss AS 5.
I haven't tested it as part of JBAS 4.2, so that's why I didn't make a public release of it.
You could either download it from SVN and build it yourself... or you could maybe download the JBAS repository and jboss-allclient should include it.
Right, 1.4.1 is for JB 5 only - maybe you can get it to work with JBoss 4.x, maybe not.
Once we've got JBM 2.0 alpha out we'll release another stable version for 4.x (where x >=2), probably in the next coupld of months, depending on resources.