Unless you find a component that is purpose built, then you are going to have to do some creative set up to make this type of thing work. I would start with AEC which is a paid membership management tool. It will handle the subscription part of the equation and put paid members in to the group that you want.
The next part can be done several ways. I am a fan of K2 so I would probably set up a group in K2 that allows front end contributions, but no publishing rights. This would allow you to moderate the submissions before they are live on the site. AEC integrates with K2 so you should be able to make it work with a little tinkering.
AEC is commercial, you can get it here - http://valanx.org/
K2 is free, you can get it here - http://getk2.org/
Valanx does offer installation services, you may consider that if you have problems with the setup. Their pricing seems to be pretty reasonable.