Finally: another use for PSP's IR port. New homebrew from Fanjita and harleyg called "piKey" lets OE users the ability to use keyboards with the PSP. "Imagine being able to use your keyboard to control any PSP game or homebrew, and even the PSP's XMB menu and on-screen keyboard, automatically and without needing any changes to the other software. This is what piKey aims to give you."
An installer is included to make installation as easy as possible. The software is compatible with various infrared keyboards through the IR port, and serial I/O via the PSP's headphone socket. The download includes an user's manual to make things a bit easier.
The attractiveness of using a keyboard with the PSP seems limited to me: the device is a handheld, not a computer. However, it's certainly an interesting program. Download it at PSP Gen.