At least for Linux…[update: and Windows!]
For Windows and Mac it’s just a question of time…
For Ubuntu, follow instructions on QGIS Ubuntu Downloads or if you already have an installation, do a system update.
For Windows, the time is now! Follow the instructions for OSGeo4W (not the stand-alone installer) on the Download Page
OSX users should check out the KyngChaos page who maintains the lates OSX builds. Unfortunately our Mac-friends needs to wait a little longer.
In the OSGeo4W package the QGIS parts has been updated:
But you may need to wait a little time for the standalone installer.
If you want to test all new cool features go to the change log and find out what they are (some are really cool).