I don't think there are many commercial companies who would take people on on this basis, but there are thousands of open source projects who are crying out for help. And working on an open source project which gets famous is great on your resum� (Linus Torvalds anyone?) Check out the Apache Group, Sourceforge, Asynchrony, SourceXchange and no doubt lots of others. Look for free or open source projects which you like the look of and get in touch with the project leaders and volunteer for something. What have you got to lose?