File Moving Script in PHP

I have a busy, active online store, where we sell digital products. I have a numebr of vendors who sell through the store. They all have their own FTP area in which to upload their products. These then need to me moved manually to a specific folder that the cart looks for to download them when someone buys them. What I would like is a script that will move the files from these individual FTP areas to the main download folder at the time the vendor submits their product form through the Zen cart. I know some PHP, but not enough to do this, though it seems like it should be easily accomplished, in probably an hour or so. Please do not send me canned responses. I will not even consider these.