As background: There is the Java SE standard specification which is governed by the JCP and several implementations of the SE standard. Currently, Sun owns the Reference Implementation (RI) of Java SE, although the Java ecosystem (i.e. IBM, BEA, Oracle, Sun, Apache, etc.) all have alternative implementations.
Geir Magnusson Jr. points out that Sun’s intentions to date around open sourcing Java are really tied to open sourcing their implementation of Java SE, and do not really impact the governance of Java, which is still the JCP’s role.
Mike points out, correctly if you ask me, that open sourcing the Java SE RI without addressing the governance of Java will leave many in the Java community waiting for the other shoe to drop.