According to Famitsu.com the rumour going around the net that back catalogue games will be free to download is not true. Speaking to Famitsu, Nintendo President Saturo Iwata said (rough translation):
"Though the baseless rumour flows in the internet that the virtual console download service is free, it is not scheduled to deliver it in free. Maybe download it (old games) as a privilege when consumers buy a new game, maybe downloading it by consistent of the campaign at limited time, variety methods will be used. Using the properties in the past, I want to take shape that the profit is paid to Nintendo to the end."
Iwata does suggest that a reward scheme may be used where people buying new games get to download back catalogue games for free or discount prices. This could be the next-gen incarnation of the Nintendo Stars catalogue.
Pro-G did not jump on the rumour bandwagon promising free game downloads, but more accurately reported that Nintendo had said their online service would be free, not the back catalogue games.