Good file hosting service that lets me sort my files by tags?

[enwar3]

So I'm looking for a file hosting service where I can upload files to share with my student organization. The thing is, I'd like to be able to tag these files and to sort the files by tags. For example, I could see all the files with the tag "Grammar" or "2010". Anybody heard of/used a service like this? (Free or paid).