The DS has outsold the PSP by a fair amount. Something like 22M units to 12M units. The PSP has 1 blockbuster title (1M+ units sold) and the UMD is a failure as a movie format. The DS has at least 12 blockbuster titles.
Nintendo is on target to push 4M Wii units this year. Sony is only predicting about 500,000 and they haven't even started production yet. There is a very real possiblity they won't be able to ship for Christmas. If they give MS a 2 Christmas and Nintendo a 1 Christmas lead, they're done. Sony is losing 3rd party publishers and Nintendo is snapping them up. Its all about install base, as this generation and the PS2 proved, not superior power. Sony has priced themselves outside of the 100M install base they had this time around. They're predicting a $3B loss in the first year of launching the PS3. That's half the company's reserves.