Image/Video/Audio gallery that allows for public posts?

I am helping someone set up a WordPress site and they are looking for a plugin that will allow them to grant permission to anyone to upload an image and/or a videoclip with an audio podcast… This seems to be a very custom application, but I could utilize any plugin that would, in essence, create a blog that the public could contribute to.

Does anyone have any ideas how I could work this or of any plugins that already do this?

Cheers!