One thing that's important is to visit the website of the company so you have some idea of what they do and how big they are and what kind of culture you might expect. Remember the interviewer(s) are going to be judging you not just on your resume, but the kind of preparation you've done and the questions you ask.
It might be a good idea to check your online presence. Google your name and see what pops up. Many companies are using services to find out what crazy stuff has been posted about you. They can't use stuff like your race or age that they find online to not hire you and they will inform you if you're not being hired because of something they found. Here's a link to a good blog on the subject.
If you've been following my instructions, you'll also have a webpage or a blog by now. Check all the links on your site and make sure they are up-to-date and active. Update all the information and make sure it is accurate. If you have a common name, make sure you have differentiated yourself from other people you might be mistaken for.
Lastly - and you may think this is weird - get some business cards. Yes, I know we live in an electronic world but business cards are still the currency of business introductions. If you're in graduate school, lots of programs will provide you with nice cards, but even if you have to go to Fedex you can get 250 cards for about $20. They might even be cheaper in a local copy store. For any kind of networking, you want to have cards.
