So yes it's only a change in the name.
On February 8, 2012, your “PlayStation®Network account” will be renamed a “Sony Entertainment Network account” or a “SEN account” in conjunction with Sony Computer Entertainment’s PlayStation®3 system software and PlayStation®Vita system software updates. (Note, this change will not be applied to the PSP® (PlayStation®Portable) system at this time.)
This transition is based on Sony’s goal to enhance its unique digital entertainment offering. As a series of these activities Sony started last September, PlayStation®Network will be aligned with “Sony Entertainment Network.” This helps us get closer to our goal of establishing a global comprehensive network platform of services across games, movies, music and more, all accessible from one convenient account.
Thank you for your continued loyalty and support during this transition.
The Sony Entertainment Network Team