What file receive method does the server you're transferring to use? (That's the only method you can use on the server you're transferring from.) If you own both servers, you can run an FTP server on the receiver, and FTP PUT the files to it using PHP on the server that's sending them. The PHP FTP manual pages have examples for each function. (Remember to error-check, and advise the user if the transfer failed.)
don't use php to transfer big files.. use rsync or just a bash script using wget.. is going to be a lot faster. Also don't forget to make sure you are transferring data packed.
try FileZilla its an FTP Transfer Protocol free software that does the job. Otherwise if you want it to run on your own webpage. You'll need something like FTP program search google there is one, it works decent and costs around $100.
You don't need an FTP program to do FTP from your web page - PHP does FTP all by itself. All you have to do is write the code.
right, but if he's looking for a solution that's already complete. There are many File Uploader programs available starting at average of $45