Here is a run down on what my conversion script does
1) In all the directories in /home/QtPalmtop/apps it comments out the "Name[ja]" line in all the .desktop files. - this causes qtopia to display the English name of the application instead.
2) It also does the same for __*.desktop files in /home/QtPalmtop/apps (these are your menu entries)
3) In /home/QtPalmtop/etc it does the same thing yet again for the files in the directories - colors, zstyles, zdecorations, & zthemes - so that they display in English in the styles applet
4) It goes to /home/QtPalmtop/i18n/ja and then removes all but the following .qm files - libcrim.qm libjpn* (note you may want to keep libqpe.qm if you are ok with the Japanese date format and having some pop-up boxes in Japanese instead of English). The *.qm files are the application specific translation files, when qtopia can't find them it reverts back to the default language (which is almost always English)
5) Deletes word-eucJP.rc in /home/QtPalmtop/bin to revert HancomWord menus to English
6) In /home/zaurus/Settings changes FontLogicalSize=0 to FontLogicalSize=-1 on todo.conf to give more space in the todo dialog boxes - not necessary if you use ko/pi
7) If the files movieplayer.qmid and libsl.qmid are present in the same directory as the script it copies these to /home/QtPalmtop/i18n/ja/ - This fixes the menus in the Sharp MoviePlayer that default to Japanese.

Finally tells the use to reboot or run "killall qpe" to see the changes (note "qcop QPE/System restart()" is now my prefered way to restart qtopia)
That's all the script does, I only wrote it casue I was experimentiong a lot and needed to reconvert everytime I reflashed or reformatted the rom.
Let me know if you have any questions
Stu