Sony has hinted @ cell being in PS3, but nothing has been confirmed one way or the other
As for the $375+ million, that alot of money considering sony is in collaboration w/ NV to create this GPU, which means that Sony is covering some if not half or most of the cost of development. That money should be nearly all profit especially if Sony were to manufacture it themselves. (they built all those fabs for something right?)
p.s. If they were to work out their deal like N did w/ ATi, then there was also no mention of if they get a royalty off of each game sold.
I believe N gave ATi $2 per system and $.50 per game and that would tally out to a whole lotta $$$$$$$ in the end.