WordPress yesterday announced the third release candidate of 3.0. They are hoping that this will be the final release before the official stable version of 3.0 is released to the world.
The announcement was short and sweet and didn’t explain what has been updated in this release candidate. Nor are there any pages in the tracker detailing what has been updated. Therefore I assume that this update just addresses some minor errors and tweaks some of the new features.
If you have been using the latest beta and release candidate versions on your site then you may want to upgrade to RC3 though I would advise holding off upgrading your live sites until the stable version is out. Make sure you to test your theme and the plugins you have installed against this version if you are using it.
Link: 3.0 RC3