It's a PDA, it's a GBA, it's a something else, what is it? Will it replace my Axim? Will it replace my phone? Will it talk to me? What will it do. So much power, so many questions, so what are you waiting for, check out the site...

[ GBA SSP PDA And then some... ]

The Nintendo DS will play GBA games for backwards compatibility, but that's all, no GameBoy or GameBoy Color support. I don't think that's a bad thing, though. I'm sure that will help keep the price down, and I have so few GBC games and no GB games, and 4 GameBoys (2 GBA SP, 1 GBA, and 1 GBPlayer), so finding a console to play the couple of pre-GBA games shouldn't be hard.

As for interactivity, they already have more good ideas about what to do with the DS than all the ideas they've come up with for GBA to GCN connectivity, so I think the DS is going to be a winner.

Update: Can't tell the form factor from the pix? Check this out: