After some turbulent hours of confusion over this story, Sony finally got its facts straight and let the world know that it is in fact not going to discontinue its 60GB PS3 in US once current stock runs out. According to SCEA's Dave Karraker, "As announced this week, SCEA's product offering in North America consists of a 80GB PS3 available in August at $599 and a 60GB PS3 available now for $499. We have will have ample supplies of both models to meet the needs of our consumers for the foreseeable future." Apparently the confusion arose from Sony Europe's David Reeves explaining that if they cut the 60GB price in Europe, they'd run out of stock in Europe by the end of July. So, false alarm people, please resume buying / not buying your $499 60GB PS3s in an orderly manner.
Update: This has been semi-contradicted once again, with Sony now saying that they have enough stock to sell 60GB consoles for the next few months, but it doesn't sound like they'll be making any more after that. According to Karraker, "We won't be making any further announcements regarding our PS3 model hardware strategy in North America until the 60GB model is exhausted and market conditions are evaluated."