The consultingcase101.com does an excellent job of breaking down difficult consulting case interview questions in a simple manner that is easy for students to understand. The site's biggest strengths lie in its categorization of cases based on case type, industry, and consulting firm.
I used their resources to prep for McKinsey PST test and case interviews. Eventually I received 3 full-time job offers from three different management consulting firms. I will be joining one of McKinsey's European office in May