Sony Estimates the Number of Actual PlayStation Network Users
During Sony's quarterly earnings report, there was a Q&A held between Sony executives and market analysts, and Robert Wiesenthal - Executive Vice President and Chief Financial Officer of Sony America - revealed, to quote:
"I think right now close to half of our users have opted to sign up to the [PlayStation] network, and I think it's running on track, and we are expecting really great things this year from it".
Not an exact statistic, sure, but it gives us a rough idea. There are 23 million PS3 consoles out there. If "close to half" of all PS3 users have signed up, that gives us around 11 million people actually signed up to the PSN on their PS3's.
Not sure whether he also included the PSP in that statement, but seeing as online use hasn't been as important for that system to date, we'd say he's not.