I saw this post on 10 Tips for Programmers to stand out at work. It’s a good piece if you’re a programmer and want to move up in your company, or get more money/responsibility/whatever from your current employer.
However it’s also a great post if you want a new job. The same types of things you would do inside your company are valuable in presenting yourself to prospective employers. All of these items are good ways to show that you are really a professional.