I'm an open source driver developer, and I've been involved in the hiring process for our driver team. From my experience in hiring: Participating in any open source project you're interested in is the best way to recommend yourself as a candidate. We get to totally skip the resume[1] and the write-some-code-on-the-whiteboard BS, because we've already googled you and looked through the actual patches you've made and how you interacted with other developers on the projects you've tried to work with. The interview process then becomes "let me tell you about our group and what it's like and some things we might be interested in you working on."

[1] (actually, a bachelor's degree in something is required. CS does not score bonus points)