>I'd recommend reading up on fair use and using your own brain. Case law is especially useful, i.e. many fair use cases regarding software have been to the supreme court - if you find a ruling covering something similar to your project then that is a good sign - Wikipedia and Google News are your friends.

I wouldn't do this for myself and I am lawyer capable of doing this sort of work for someone else.

You bias your own research when you are too close to the matter.

If you want a good rule of thumb for commercial fair use: Don't use copyrighted material at all unless you are doing a clear parody.