I honestly wish they had somehow made a way to export images and videos =/ Would have helped a lot.
There are several ways to get video from the game, I just don't think there's a way to convert the files saved on the PSP to video files. All of the methods involve playing back the performance and recording it externally.
Some of the methods:
Although to use this you'd have to hack your PSP, but the program lets you record gameplay off your PSP. I think a majority of all the clear PSP videos on youtube use this method. It's sadly the cheapest and easiest way to record off a PSP, it's just you'd have to go about hacking your PSP.
2) Composite cable to DVD recorder-
If you have a PSP 2000/3000 there's a slot at the bottom to connect a cord to export psp screen to a TV screen. If you run it through a DVD recorder you can record the performance onto a DVD, then rip that DVD to your computer and upload it to youtube. Only major problem being that it won't be crystal clear and when you export gameplay off a PSP, it does this stupid borders thing and scales the image down rather than fill the screen.
3) Composite cable to capture card-
Same as 2) except instead of feeding the cord from the PSP into a DVD recorder, you feed it into a USB capture card or something that takes composite input. It's a pain to setup a capture device, the one I use is temperamental but it's easy to use after you figure it out. You can record video, zoom in, etc. However like DVD recorder it still isn't high quality...but if you team up the device with an audio recording program you can record audio from the game live and stuff 8D