(I no longer use the Sharp Zaurus and do not maintain these pages. I have left them here in case they are useful to someone.)
If you are an English speaker, you will need to convert your unit to the English language. This means changing the ROM (basically, the operating system) and the applications you use.
You can get a converted unit from Dynamism or from ShirtPocket. Alternatively, you can buy one in Japanese (eg from Conics) and convert it yourself (for example, by installing the Cacko ROM or tkROM -see below.)
Because the Zaurus is an open system, you can install a different ROM. This is the first thing you may want to do.
I am currently using the Cacko ROM. Details of how this is set up are here.
I also used the tkcROM, but this is no longer in development. Details of how I installed this are here.