What was your major in college? (For testing purposes a hard science major with many hours of lab experience is better, but not required)
How does it [The scientific method] apply to testing (generally)?
How does it [The scientific method] apply to the type of testing position you are interviewing for?
How does it [The scientific method] apply to documentation and requirements?
How would you test a <insert mundane object here>? (toothpick, paper clip, alarm clock, bowl, glass, etc....)
What are the core differences between "white box" and "black box" testing methodologies?
These are just a few of the items which come to mind. Be prepared for any questions related to methodology and a practical demonstration of knowledge. There are many classical examples of what you might be asked to test, but if you have a good interviewer they will provide you with something which has not been discussed in texts on testing: Here is where the practical application of knowledge comes into play when you are faced with a new challenge.
As with any interview, demonstrate your level knowledge and comfort with your skills well. be confident in your approach to problems. How you think and approach issues is as much under examination during your interview as is your background.
What are the responsibilities of a software tester?
What is a bug/defect?
What do yo do when you find a bug/defect?
How do you write a good bug report?
What is regression testing?
What is the difference between white box and black box testing?
What is a test case?
What is a test plan? What would you expect to be included in a test plan?
When do you stop testing?
What do you do when a developer/engineer tells you they cannot repro a bug you have reported?
How do you feel about Automated testing?