While we’ve known the native Japanese PlayStation Portable Store is shutting down effectively March 31st of this year, it seems like North Americans will also be included in the closure of the service.
Sony Computer Entertainment America confirmed (also via Twitter) the same date, March 31st, for when the native PlayStation Store on the PlayStation Portable will be shut down.
It’s worth mentioning you’ll be able to download past purchases on your PSP, as well as in-game purchases (like downloadable content).
From then onwards, the only way to purchase games is via the web-based PlayStation Store, after which you can transfer your games to your PlayStation Portable.