Check at GameSpot for more details.

As far as I know, the LCD screen is improved. More vibrant color and less reflective when playing outdoor (under a tree). The PSP is still unplayable under direct sunlight. Although the new LCD screen will drain about 25% of the battery power, but the power drainage from the other components will be lowered to compensate the decrease, hence providing the same gameplay time with battery on as with previous model (PSP-2000-PSP-2006)

Besides, the latest model also featured built-in microphone and TV output via both INTERLACE AND PROGRESSIVE mode! Which is a plus for those who didn't own a HDTV. Anyway, there's been a plug-in named FuSa that enable PSP 2nd gen owner to output the signal to progressive TV, yet some games still suffer terrible lag.

This post has been edited by D.Sync: Oct 2 2008, 12:00 PM