Setting up a web based FTP site?

Hello,

I'm not sure if this is the best forum for this - if not, please let me know.

I have a hosted web site that offers FTP access for users.
It's not the simplest process for users to use, and I'd like to make it simpler, but am not sure where to begin.
I'm hoping to create a web based FTP site, where users must log in, and they have the ability to upload, download, and create directories.
I haven't been able to find any suggestions/directions through searching.
Can someone point me in the right direction??

Thanks
Amber