Sony is readying the Sony PSP firmware 4.00. Update: Sony PSP Firmware 4.00 available now

The Sony PSP firmware 4.00 is adding Google Internet search directly to the XMB interface.
The Google search on the PSP will be able to recall your last 20 searches and gives you the same experience as searching directly on Google.com.
Another new feature delivered through PSP firmware 4.00 is the ability to change viewing speed during playback of videos stored on your Memory Stick PRO Duo.

Usually when Sony pre-announces a new firmware it is released in Japan the next day. This time the new firmware 4.00 is not published yet.
Via the Sony Playstation Blog.