It seems doubtful that they would do this. 95% of NES and SNES games, Nintendo simply CANNOT unilaterally release for free, because they're other people's IP. For the 5% of games for which Nintendo and Nintendo alone owns the rights, well, they've been selling those or bundling those for a while now, so the idea that they would make some of them part of a 'deal' of some sort makes perfectly good sense. But releasing their entire in-house games library for free sounds very unlikely, while releasing the entire NES and SNES libraries as a whole would be legally impossible. Completely incoherent with their previous use of their old titles, and doesn't appear to make much business sense. Possibly for low prices, but who knows what their plans are there.
<{POST_SNAPBACK}>
What a lot of people have been thinking is it will be similar to iTunes or such. Pay like a dollar per game. Since most of these games aren't being sold anymore, its more than they'd get otherwise.