The change, however, is purely cosmetic. Your account will still function in an identical fashion and it will not be necessary to change your username or password; the PSN itself remains unaltered.
"The goal is for there to be one networked log-in for all Sony services," a Sony spokesperson told us after news of the switch made its way to neoGAF. "Changing the name 'PlayStation Network account' to 'Sony Entertainment Network account' helps clarify the unity between PSN and other Sony Entertainment Network services." The change does not apply to the PSP, so users will still see "PlayStation Network account" when logging on with that device.