This is actually some pretty big news, because up to now lane-sharing has occupied a legal gray area: not illegal but not really legal either.
But thanks to some hard-working and persistent folks at the Bay Area Riders Forum, the CHP has now publicly acknowledged that lane-splitting can be done safely and is not necessarily dangerous.
California Motorcyclist Safety Program
1 down, 49 to go
(On a personal note, I was involved in this process and actually wrote a very early draft of the guidelines 3 years ago; the final result is quite different, but some of my verbiage is still in there.)