I have a Masters degree in Interaction Design but I'm starting a graduate job for a large IT firm doing systems architecture.

However, I would like to carry on doing some work relating to interface design/user experience/interaction model design. I'm kind of new to this whole open source thing and it seems to be quite impenetrable to people who don't write code. As such, I was wondering if anyone had any advice they could give me on how I could contribute to open source projects in a non programming role. I can produce designs, low-fidelity prototypes and advise on usability issues etc.

I don't have a portfolio as most of my academic work has primarily been in the theoretical Human Factors paradigm relating to assistive technologies.

Thanks!

*Edit: I should also add that if anyone has a small project on the go, particularly if it's related to mobile platforms and would like some help with interface design I would be willing to help. I should say that I favour accessibility over aesthetics. Although you argue that aesthetics affects usability (but that's a rather complex discussion!!)