It's tracking well below, although the GBA declined very fast at this point in it's life. The PSP looks like it's rapidly declining too, and it's relevance is becoming less and less.
Production costs are likely much higher for PSP than GBA also, so I don't see it moving down in price much to increase demand. Sony probably would drop prices a lot, if they thought it was worth going 'razors and blades' with PSP again, but considering the sales of blades, I doubt they will.
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.