In the wake of Apple CEO Steve Jobs' resignation on Aug. 24 -- and the promotion of former COO Tim Cook as his successor -- we thought it a good time to take a close look at Apple's executive leadership. In one way or another, the executives included here have proven integral to the development of Apple's brand and its ongoing success. Although the company hasn't always been the most CIO-friendly firm in the technology industry, its executives have far more impact on the average enterprise than you might think. The fact is, Apple's products are becoming increasingly popular around the world, including in the workplace. And even Apple's harshest critics have to acknowledge the appeal of the firm's mobile products, especially the iPad, and accompanying applications. Here's what you need to know about the five key executives at Apple that really matter to CIOs.