Did you know that Eee PC can be used as an external display for PSP? Well, now you know. Actually any PC or laptop can be used for the same purpose as long as it runs Windows and RemoteJoyLite. However I doubt you will be carrying around something heavier than Eee PC, if you have one.

PSP hooks up to Eee PC via USB. Very simple, no catches. Just keep in mind that neither Sony nor Asus support this kind of tweaking.