BHP Billiton standardized on the TopGrading (http://topgrading.com) methodology for hiring. Basically, be prepared to answer variations of the same 5 questions about your last 4-5 jobs or companies you worked for.
1) What were you hired to do?
2) What were your high points?
3) What were your low points?
4) What would your boss/peers say about your performance?
5) Why did you leave?