Power up your PSP and try to connect to the PlayStation Store. Just try it! I dare you!
You'll likely be prompted to upgrade your system to the latest firmware.
Yes, the PSP's internal software is getting an update today. The system can now be upgraded to system software version 5.51.
As suggested by the tiny decimal increment, this just just a bug fix update over version 5.50. The update makes some unspecified fixes to software operation.
Version 5.50 of the PSP firmware, released April 21, added a number of features, most notably an Information Board which gives users access to the latest PlayStation-related news.