Publishing a spreadsheet online
 

I have a spreadsheet that's a combination of data input sheets and graphs
(which are created based on the data). I need to send this spreadsheet out to
a large number of people, and I'm wondering whether there's a way to publish
the spreadsheet online, where people can input data and see the resulting
graphs, but not be able to see or change the formulae in the spreadsheet.

Essentially, I'm looking for a way to publish a protected spreadsheet online.