A web file manager can be a very useful tool. The best one I have found so far is this:
One of these needs special PHP settings to run well (especially to handle large files), and if you’re using hosted web services, you’ll want to do this by special lines in the .htaccess file. The below is satisfactory if your provider’s web server is very powerful with lots of space reserved for you; if not, reduce reduce reduce!!!!!
php_value memory_limit -1 php_value upload_max_filesize 800M php_value post_max_size 800M php_value max_execution_time 50000 php_value max_input_time 50000