Apparently you can. PSU member AznBoiz has posted over on the Official Sony Forums that this is possible through the use of Remote Play. Not only can you use it to control things such as browsing ...

For part 1 of this project we're going to learn how to attach an analog stick to one of the PSP's internal circuit boards. You can then use this info to build a custom joystick "clip-on" device ...

Basically, you run a web server on your PC that serves up a PHP page from which you can control iTunes that fits ever-so-nicely on your PSP's screen.