It is possibly best to talk to talk to teacher. You can pose it in the form of a question: "Hello, I am from X. Because of my personal interest in GNUstep (which is an open source implementation of <insert your own description here>), I wonder if you are aware of Google Summer of Code? Students get to interact with an open source community, contribute code and earn some money." After that, it depends on the teacher.
Teachers know students and may (ideally should?) be interested in students practicing software engineering.
Other than that, email, forums, etc. are good. So is talking to your friends. I'm not sure other offline methods are worth it without support from teachers.