From Playstation.com:

"The PSP Firmware 2.0 Upgrade for the North American market will be available during the week of August 15th, instead of on August 12, as previously reported.

Designed to compliment the comprehensive entertainment experience of games, movies, music, photos and wireless connectivity provided by the revolutionary portable device, the firmware 2.0 upgrade will allow users to take advantage of the unit’s built-in Wi-Fi capability and wirelessly search the Internet from Internet Access Points or hot spots. The firmware 2.0 upgrade will be available for download directly to a PSP using a Wi-Fi connection or downloaded to a PC from http://us.playstation.com/psp and transferred to a PSP through a USB cable."

Here was the information from the Japanese v2.0
- Network
Internet browser added

- Video
Jump function added (UMD Video & UMD Music)
A-B repeat function added (UMD Video & UMD Music & videos stored in Memory sticks)
"4:3 mode" added to Video mode (videos stored in Memory sticks)
Sound mute function added (videos stored in Memory sticks)
MP4 (AVC) format playback support added (videos stored in Memory sticks)

-Music
Can accept music tracks in Atract3 Plus format from "Sonicstage" under version 3.2 (now for pre-order)
MP4 (AAC) & Wave (Linear PCM) format playback support added (music stored in Memory sticks)

- Photo
Wallpaper function added
Image receiving function added
TIFF, GIF, PNG, BMP format supported

- Settings
"Character set" added to "System settings"
"Theme settings" added
"Internet browser startup limit" added to "Security settings"
"WPA-PSK (TKIP)" added to security method in "Network settings"
Keyboard now support web input.
* All the setting before the upgrade will be preserved.