First you need to download JBoss Microcontainer release from http://labs.jboss.com/jbossmc/downloads
Unpack the archive which will give you a microcontainer-x.y.z directory with the following subfolders:
docs/api - javadocs for the Microcontainer
docs/gettingstarted - this getting started documentation
docs/licences - the licenses for the software
examples - the examples explained in the next chapter
lib - the libraries required to run the Microcontainer
You will also need a JDK of version 1.4.x+ and a copy of Apache Ant 1.6+
If you want to run the examples inside JBoss AS, you will need to download JBoss AS 5.x http://labs.jboss.com/jbossas/downloads