Well, the PSP does have slightly better graphics... but not much... (which we were aware of, but I dont trust screens until I see the real thing) Its hard to compare the 2 based on those screens... The DS will have a more GC style to its 3D, and the PSP will have a very PS feel to it. The GC has just as nice graphics as the PS2, its just they have a different feel to them. I've always felt that the PS2's graphics have always had a very ridged and pointy feel, while the GC has always been real smooth.
basically, that pic of snake looks so nice, cause they did a good job on the textures... when used corretly, textures can make something look more 3D and detailed than it really is. Something in my mind makes me doubt that pic... and its also bigger than the DS screenshot, to make it look better... but the screens are in reality, about the same size... the PSP is not as tall of a screen as the DS, but its wider...
The only think I can say, is that the PSP will probably have slightly better screen resolution... (more dots per inch)
With Nintendo's experiance in hand helds, the obvious extra/better features of the DS, and the abillity to play games from the GBA on the DS... The DS will be the leader in portable gamming.
The PSP seems to only have graphics (if that) in its favor, and is missing a lot of valuable things (like battery life), that will push gamers tword the DS.
And for those of us that already own a GBSP that means we can still play those old GB-GBC games. ^_^ so its still a nice system to have, plus its gone down in price so much. XD