The remaining PSP PSN Stores will close as of 31st March 2016!
The Playstation Portable devices have their very own Playstation Store, that they can access via their XMB (PSP menu).
The PSP Playstation Stores for the PAL-Region (Europe, Africa & Australia) have already been closed down, but the ones for the Americas & Japan were still available.
This is going to change as of April 2016.
This change will mean that it won’t be possible to use the PSN store via the PSP device itself anymore, and one is required to use the PSN store via a Computer.
You will still be able to transfer content onto your PSP, but this will require the PC Software MediaGo. Only wireless purchases & downloads via the PSP will cease to work.
For purchases one has to use another Sony device, such as the PS3 or PS Vita, or simply the PSN-Store website via a PC or mobile device.
Source via Twitter.