I untar them all of the time using Winzip 8.0 -- I think I have used Winzip on them all the way back to version 6. Sounds like there is a problem with the tar files, or they are not really tars at all, but perhaps .ipk (tar.gz), or ar. If you\'ve downloaded files from ZSI, most of them are not .tar, but one of the other formats I mentioned.
To untar a file on the Zaurus, you need to have a terminal program, such as embeddedkonsole, installed. Then it is a matter of:
tar -tvf tarfile.tar to list contents
tar -xvf tarfile.tar to unpack the contents