file upload progress bar

I am using wordpress for a customer that operates a sign company. His customers need the ability to send very large art work files to him. I want to setup ftp capabilities from the wordpress site that will allow the his customer to browse for the file and submit it to the site. Because these are very large files, the upload can take some time; therefore, I would like to show the customer an upload progress bar. Does anyone know how to do this with wordpress/php?