online file hosting

I'm looking into a new concept that I've been really thinking about. I want to make a service where people can log in and upload their own files (NOT just images). Simple enough. Each time they log in they can see their files, delete them, add more. Pretty much use it as an online backup database. Now What I'm wondering is how would I set it up? How can I limit certain customers (free customers get, say 100mb free space, while a premium member gets 1gb)? I've always been using MySQL, but I'm not sure if this will be the best as I never did anything this advanced.

The other thing that I need to worry about is making sure I can access my account from a desktop application. Hope I can get someone to point me in a good direction, maybe even a certain book/chapter?

 

This is definitely not a new concept, check out e.g. Google Docs for something very established which does just that.

You could look into unix admin/shell etc. kind of stuff. Perhaps your system could just interface with a server like that.

 

Well I know that isn't new, but that is only partial to what I will be trying to accomplish. Just not wanting to give out all the details.

 

You would write a script, i guess the "user" would have a directory created in his name or account number
You'd then have a script that detected the files and sizes in this directory and know how much space he is using.
If over X space.. sorry, please upgrade in site code