I should perhaps emphasise that this change of access won't affect any AAS readers who play by the strictest Nokia rules. The most common use of third party and leaked first party tools for accessing the Nokia firmwares is to install firmwares that haven't been approved yet for a user's region. As an impatient fellow geek I can sympathise with the community here, but I can also see Nokia's point of view - with the increasing awareness of the possibility of flashing alternative firmwares, there must be a growing stream of users running into problems after flashing and then turning to Nokia to sort their device out.
The information that we know for a few days, but we do not want to alarm until we have 100% certainty that this is true. Now, however, we have confirmed through bb5unlock -ovi.
IMPORTANT NEWS BULLETIN 12-21-2012 FROM NOKIA:
Nokia will close open connection to Nokia Firmware Repository during January 2013 and Implement access control.
Ater this, the Nokia Online login is required to access Nokia Firmware Repository.
During transition phase (December 2012 - January 2013), both open and restricted channels are open, but the open channel will be closed at the end of January 2013
After this, application updates and device software downloading are possible only by using the latest software releases with service NOL login supported.
Smartmobil recommends grabbing any firmware images you think you might need before the end of January, though of course this won't help for firmwares released after that. Mind you, for the vast majority of readers here, sticking with official firmwares and official support is definitely the way to go.
Of note is that this won't affect the 'custom firmware' scene (one such on the Nokia X6 below) - these are stored on third party servers and are usually freely downloadable.