The Download Options that can be set under Preferences in Explorer can be used to force Explorer to decode binhexed files. The Application Settings under Preferences in Netscape can be used to set Netscape Navigator/Communicator as the helper application for MacBinhex files.
After you have changed these settings you can retrieve StuffIt Expander.
After you have installed StuffIt Expander you should go back through the steps outlined above and set your browser back to using StuffIt Expander to handle binhexed files.
If you aren't using Netscape or can't get the above instructions to work, you have another option if you have an FTP client such as Fetch or Anarchie. You can use one of these to get StuffIt Expander from our FTP site and this FTP software will do the decoding/decompressing: