Moderation of post with upload

I have read what I think are all of the previous posts about moderation of posts and can’t find what I’m looking for. I was hoping that someone wouldn’t mind giving me some advice.

I am finishing a school website that is using WordPress as CMS for a few pages. For most categories, if students are just given contributor accounts, their posts don’t get posted until they have been approved by a higher up. This is what I wasnt to do except that the section that the students can work on is for podcasting.

Users can’t upload files (the audio) unless they have at least (I think, a rank of author.)

My question is, are there any plugins that I haven’t fould which do make it so that every post has to be moderated? Either that or is there any way that I can get the posts with audio to slip through the filter?

Thanks,
Bimo