The microcontainer project should be released using the standard maven release process.
Checkout the project from svn https://svn.jboss.org/repos/jbossas/projects/microcontainer
Build the project using the release profile
mvn -Prelease install
This will compile, run the tests, and package the jars.
Follow the instructions on the MavenReleaseProcess page.
Upload the release onto sourceforge and link to JIRA release notes. The archives are built in kernel/output/
"Advertise" the release here: http://www.jboss.com/index.html?module=bb&op=viewforum&f=62 and here: http://www.jboss.org/products/jbossmc
Commit the maven and jbossbuild jars to repository.jboss.org
(Possibly) Update the 4.0.x branch to use this version