It's the same lead time the 360 got. Announced in May, on shelves for Christmas. The PS3 was announced the same day but released a year later, which many felt hurt them by reducing PS2 sales and giving the 360 a year of momentum over the PS3.
I don't think the year head start is what hurt them. Lack of games and a price tag that didn't seem to be justified hurt that system. The games didn't look good enough to ask for an extra $200. Plus many of the exclusive titles got delayed (gran turismo) or chopped up, warhawk, to the point of being different games.
All the titles that caught my attention didn't show up until at least a year after launch. That wasn't he case on the 360. Going forward they need a strong launch lineup.
VGfive.com - Game Trading site (Steam codes too!) Kickstarter "Game Developer"!