The links that Gizmo provides are useful. To provide some brief summary statements,
Patents protect "utiliatarian products," i.e. any device, process, etcetera that serves a function other than simply, say, looking pretty. Patents do not always protect what results from using a certain device or process.
Copyrights protect sufficiently creative works of art and the like, i.e. literary works, movies, pictures, etcetera.
Patents protect against making/using/selling. Copyrights protect against copying, and anything that derives from such copying.
If you describe an invention, copyright law has the potential to protect against someone copying your description of your invention. It will not protect your invention. If you create new computer software, copyright law will protect against someone copying your source/programming code. It will not protect against someone using their own, unique code to create a similar software program.
Meaningful patent protection can be expensive. Copyright registration is relatively cheap - and some rights exist automatically even in lieu of copyright protection. Yet, a Copyright is no substitute for a Patent.- Bill