I have posted it before, but I would say check out the dice job forums
They are taylored for questions like this.
As for advice here, give some more details about the job. Is it a part time position/internship? a co-op? computer forensics is a vast field. what exactly are the duties of the job you are interviewing for? is this a private sector, government, or contract job?
My generic advice is if you have any security/forensics related class notes/books from school, study those so that you can show you know the basics and that you have the ability to learn. Most of the time, for entry level jobs, they aren't expecting much, but if you show them you have potential, that is a definate plus.