IT professionals build, design, and maintain the systems that handle storing, sending, and retrieving information. Employers are looking for individuals who are able to systematically solve the tough and unusual problems that arise in the field. Expect to be asked many hypothetical questions that will assess your thought process when dealing with complex problems.
Outside of system specific questions, being asked how would you deal with difficult situations, which is pretty standard, but ensure you're able to follow through.
Make sure and include your documentation procedures.