For a few years I voluntarily worked for Nintendo America's Internet Piracy team. I got websites like GBXEmu closed. However after working with the team a few months I was charged with tracking down the suppliers rather then distributors. You see Nintendo goes after the people dumping the roms online rather then those taking the existing roms and circulating them.
After catching some guy in the netherlands I stopped working with Nintendo. It was becoming like a full time job and while I was morally supportive I just decided to stop.
Nintendo does alot to curb piracy but in the end the DS and Wii formats are both pretty easy to pirate. Nintendo is doing alot to catch those responsable for dumping the roms. Recently they hung an Australian out to dry after he dumped NewSuperMarioBros. Not to mention their legal battles to try and stop the sales of R4 chips and Wii mod chips.
In the end I think Nintendo in the past faught piracy the best, rather then creating a conventional format. Do something radically different. Create a format that is highly difficult to pirate. Nintendo has always been protected by its software formats from cartridges to mini-disks!
Also I think its funny to see Sony claiming their poor PSP software sales are due to piracy while I know far more R4 owners then I due PSP pirates. Way more softeware for DS is pirated then PSP yet DS software still sells!