The Japanese author calcium who created the famous video encoder 3GP Converter for the PSP, has released several updates on his great encoding tool. The latest version is 3GP Converter AVCTest 050808-2.
Calcium now is trying to implement MPEG4-AVC video encoding within his tool. Currently only PSP with version 2.0 firmware is capable of playing this high quality format. This version also need Avisynth 2.5 and QuickTime 6.5 or above support for converting formats other than AVI and etc.
You can download QuickTime 7 from: http://www.apple.com/quicktime/download/win.html
Download Avisynth 2.5 from: http://sourceforge.net/project/showfiles.php?group_id=57023
Note: The default language of the tool is set to English, so don't worry about the language problem.