Product documentation for Java ES 5 Update 1 is available on docs.sun.com:
Release notes: http://docs.sun.com/coll/1315.3
System-level installation, upgrade, and planning manuals: http://docs.sun.com/coll/1286.3
Collections of manuals for each component: http://docs.sun.com/prod/entsys.5
Additionally, you can find other kinds of documentation on the information hub for Java ES on BigAdmin: http://www.sun.com/bigadmin/hubs/javaes.