I have posted in the wiki as example on how Kepler and P2 metadata of an
Eclipse plugin look like
org.eclipse.jdt.junit in Kepler
http://wiki.eclipse.org/Org.eclipse.jdt.junit_in_Kepler
org.eclipse.jdt.junit in P2
http://wiki.eclipse.org/Org.eclipse.jdt.junit_in_P2
org.eclipse.equinox.common in Kepler
http://wiki.eclipse.org/Org.eclipse.equinox.common_in_Kepler
org.eclipse.equinox.common in P2
http://wiki.eclipse.org/Org.eclipse.equinox.common_in_P2
There are some things in the P2 Instalable Unit model that are not yet
in Kepler but could easily be implemented by adding a new facet.
I'll be at the Application Provisioning Symposium next Tuesday
http://www.eclipsecon.org/summiteurope2007/index.php?page=symposia/#provisioning
talking about this and repositories.