I discovered today this essential document any software engineer should always keep in mind. It was written in 1999 by the ACM/IEEE-CS Joint Task Force on Software Engineering Ethics and Professional Practices and approved as the standard for teaching and practicing software engineering. The full version is a must read.
In my very personal opinion, a lot of the ideas expressed through the preamble and the eight principles in the document, motivate and support the free software movement and go directly against (not only software) patents.