Most PHP scripts come with ample instruction for setting things up whether you are a programmer or not. Most of them require little or no tweaking, and those that do need settings normally limit their requirements to your domain name, username, password and so on.
Some web hosts may or may not allow file uploads and those who do will require a number of security measures to be put in place. These will include restrictions on file type, file size, multiple or single file uploads and there will also be some pretty serious security required for the destination folder where your uploads will end up.
Look on Hotscripts click here and run a search in the PHP script archive for:
There are lots of free options and most are dead easy to set up. They even have a couple of beginners tutorials click here and click here on how to script your own uploader page.
It isn't wise to offer your username and password so readily and, quite frankly, any web host that offers your PHP and/or MySQL support for nothing AND file upload capability is borderline crazy. The potential for misuse is vast.