From the H-Sci-Med-Tech listserv - the International Committee for the History of Technology put out a call for papers for its 2008 symposium, entitled "Crossing Borders in the History of Technology." It looks like graduate students are encouraged to submit papers, as well as experienced historians.
Speaking of listservs, if you're interested in history (not just the history of computing), you should investigate H-Net. You can join any number of listservs on just about any historical topic imaginable. I'm personally on the listservs for H-Sci-Med-Tech (the history of science, medicine, and technology, obviously), H-Grad (for graduate students in all historical disciplines), and H-Info (the history of libraries and information). If you go to www.h-net.org and click on "Discussion Networks" at the top, you can view the entire list of possible networks to join.