[eluser]Seppo[/eluser]
You can make a .php that reads the file and then delete it...
Code:
$target = "files/download.avi";
readfile($target);
unlink($target);
Also, you might want to check the ignore_user_abort function to avoid deleting it if the download fails.
-edit- also you should send a header before, telling the browser to download the file... something like header("content-type: application/octet-stream");