Peter Oppenheimer is only 50 according to the proxy that came out on Monday. That said, Tim Cook has yet to name a replacement COO, so it's possible Oppenheimer would make a lateral move within the C-level (assuming he's up to it - finance guys don't always make good operations people).
That said, Apple is a much bigger organization, though. It could be a nice challenge. Oppenheimer's cash salary was $805,000 last year, up from $700,000 the year before. He also got a $1.6 million cash bonus, up from $700,000 the year before. However, the real prize was the $66.5 million stock award. He didn't get any in 2011, but got $28 million in 2010.
I'd guess that the controller will probably get a salary and bonus in the $500K range each. The real money will come a bit later if he sticks around (in the form of restricted stock). The days of Apple having insane stock price growth are probably over, but they should still be a solid high margin company for some time.
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The controller is the head accountant and usually reports up to the CFO. In most organizations the CFO manages both the corporate controller and the corporate treasurer. On a side note, with over $100 billion in cash and investments, Apple's treasury department is a behemoth of its own. It's the equivalent of a large bank.