Mike
You can create a user account for your friend and then get him/her to VPN into your server and upload the files that way, setup appropriate access rights to the ibay for the user account and it will work OK. Nice and secure too.
Alternatively the user can ftp to a user home folder and upload files, it could be the user account mentioned above or a user account called uploads, for which both you and your friend share the password. Not so secure.
You could also instal the webshare rpm and this will create a folder (or folders) that can be securely accessed from the web, and users who have the password for the webshare folder can upload and download files, it's useful for a number of users collaborating on a project. It worls quite nicely except the webshare folders are in /opt not in an ibay. Uses htaccess so its nice and secure also.
You could also use scp to securely connect to the server and copy files, (use a program called winscp2.exe or similar). Secure also.
A year or so ago, there were quite a few posts on enabling ftp uploads to ibays, do a search and a lot of reading and you'll find something. It did require some command line work to do, and keep in mind that ftp is inherently not secure.
Hope this helps and one of the methods suits your needs
Regards
Ray Mitchell