http://psp.connect.com/
Sony has uploaded a few videos for the PSP there, although you can convert them to play them on the GP32
They're 320 x 240 and in MP4 format. Included in there is an entire Speed Racer episode, split into two parts! It brings back so many memories from my childhood 
Sony has uploaded a few videos for the PSP there, although you can convert them to play them on the GP32