What is Korona?
Korona is a live DVD that makes it easy to peek at the current state of porting KDE4 to OpenSolaris. It's created by adding the packages of the KDE-Solaris project on top of regular OpenSolaris image. Apart from setting KDE as default, there are no other customizations.
Can I install Korona and use it in production environment?
Please don't :-)
Korona is not really a distribution. It's meant to be a test-drive thing.
If Korona is not for you, then have a look at Belenix.
If you like Korona, you may be better off installing regular OpenSolaris and installing KDE from the KDE-Solaris IPS repository (check the forum for latest news).
So what works and what's broken?
See the Status page.
I want join the developers/build my own KDE packages
A step by step guide is available.
There is a forum. Developers hang out at the #kde4-solaris IRC channel of Freenode.