Here's the official Sony PSP-3000 versus PSP-2000 LCD comparison image. Click to see full size.

Sony added the antireflective technology to improve the PSP's outdoor playability. We took our two PSPs outside for some side-by-side testing under the bright California sun. Neither system was playable in direct sunlight, but the PSP-3000's display performed better than the 2000's when we took a look at both systems in a shady area beneath a tree. We had difficulty taking pictures of the PSP's antireflective screen in action outside--please bear with our angled indoor shots. The new system has the same video-out port and uses the exact same video cables as the PSP-2000, but Sony has upgraded the PSP-3000's video output to support gameplay output on interlaced displays using composite video cables. The move will surely excite gamers dismayed over the fact that the PSP Slim can output gameplay video only to progressive scan displays. Now they can buy a new PSP instead of an HDTV.
The PSP-3000's other major upgrade is its new built-in microphone. Sony put the integrated microphone into the PSP design roadmap after seeing the success of the headset-enabled SOCOM: U.S. Navy SEALs Fireteam Bravo. Sony placed the microphone pickup beneath the screen to the right of the volume buttons, well out of thumb reach, to prevent any inadvertent muting.