As of 9am (UK time), today, 12 September 2012, OpenStreetMap is now licensed under the Open Database Licence.
Thank you Open Data Commons for making legal tools available for the Open Data community.
[Update: Friday, 14 September 2012 approximately 18:30 UTC]
The XML-format Planet file took longer to generate than expected. It is now available in the new directory structure at http://planet.osm.org/planet/. You may experience slow downloads due to demand at this time.
Additional PBF-format files will follow as soon as they are completely generated.