Sony really didn't exactly react to the 360's price drop (yet), but they officially announced the 80gig PS3 and added this:

The 80GB model joins the existing 60GB PS3 that has been available at retail since launch last November. The 60GB PS3 is currently enjoying a surge in sales following a price reduction in the US and Canada on July 9 of $100 to $499/$549 CND. Since that date, unit sales at the company's top five retailers have jumped 113% when compared to the average sales of four weeks prior to the price drop. SCEA will continue to sell the 60GB in the US and Canada at the new, reduced price until current inventory is depleted, which is predicted to be this fall based on current consumer demand.