NES games on Wii

I recently booted up my Wii and saw the original Mario Bros. and Mario Bros. 3 on my channel home screen. I had bought them back in the day and I am now wanting to get more NES games. Is there a way for me to rip NES games onto the Wii? Can I just rip the ROM's straight from the NES section and transfer the files over or do i have to go through some other kind of process? If not, are there rips of the old NES games that were sold on the Wii Shop Channel?