Not unsurprising considering that's the average price of an Xbox 360 game, Kaz Hirai hinted in the most recent issue of PSM that games for the Playstation 3 will probably cost the same. His actual comments are a little vague, though:
"Generally Speaking, over the past twelve years or so, there has been a consumer expectation that disc-based games are maybe $59 on the high end to $39 on the low end. So, what I can say now is, I think it would be a bit of a stretch to think that we could suddenly turn around and say "PS3 Games now $99.99." I don't think consumers expect software pricing to suddenly double. So, the quick answer is that we want to make it as affordable as possible, knowing that there is a set consumer expectation for what software has cost for the past twelve years. That's kind of the best answer I can give you. So, if it becomes a bit higher than $59, don't ding me, but, again, I don't expect it to be $100."
In the end, Kaz doesn't seem to know exactly what they'll cost, either, which is admittedly a bit discomforting. While costs of manufactuaring Blu-Ray discs aren't sky high, they could still impact the retail price in the end. Either way, with the console already costing far more than the competition, it'd be a hard sell for Sony to price software any higher.
If you'd like to read more of the interview, pick up the August 2006 issue of PSM.