This is not Legendo's POV, it's my personal (I'm Dan) pov.
Let's face it, Nintendo knows how to make handheld hardware. I think it'll be a huge success, it may take a little longer to take off than say the DS but people will snap it up once they've seen it in action. From my own personal understanding, it may use lenticular lenses (like the 3D posters you can get) to give the 3D effect which sound rather odd but I'm sure that Nintendo know what they're doing and I can't wait to see some first party titles running on the machine. My only real concern really is the negative impact that 3D has on some peoples' eyes. Mine for example, when I try to watch anything 3D whether it's the classic red and green lenses or active shutter or even just the polarised, it literally feels like my eyeballs are being pulled out. The way I get sucked into games, I can see this giving me some real bad headaches if the technology's not right.
I was at a tradeshow recently here in the UK (Gadget Show Live) and I met up with nVidia who I interviewed. As impressive as the whole 3D scene is it just still feels like a gimmick that may wear off at any moment. We seem to hit a 3D fad every ten years or so!
We're not currently developing for the 3DS, I imagine that the dev kits that are out in the wild are in the hands of first and second party developers. Whether or not we'll develop for it, who's to say! I daresay it'll all boil down to pricing of the dev kits, sales of the hardware and what kind of infrastructure Nintendo'll offer for digital distribution.