Sony has updated PlayStation Portable's firmware to version 3.73.
The new firmware supposedly fixes a flaw with the UMD drive. Apparently in some cases data would fail to load properly, and Sony appears to have solved that problem.
Not the most exciting news in the world, then, but undoubtedly important news to anybody who's been suffering from the above-mentioned UMD-knack.
You can download the new firmware from Sony's website (if you can bloody find it) or by using the Network Update option on the XMB.