I still don't know which Zaurus model you are looking for software for... If it is the SL-5500 / SL-5600 then go to http://myzaurus.com
and 'Downloads'. If it is the SL-6000 then don't go there.
If the model you have is the SL-6000L (USA) then I think Sharp is hosting this at SharpUSA. I just went through registration athttp://sharpusa.com/zregister
and I was eventually able to navigate to http://sharpusa.com/products/TypeSoftware/0,1086,112,00.html
which is 'Products & Support' ... Business ... Handhelds .. Zaurus Enterprise Mobile Tool ... Software
and download hpc_soft_installcd.exe
I don't yet know if this is the correct file since I'm not running Windows to unpack it.