Col said it well, but if you have have the chance read Steve Collins book Good to Great. IT should support the core business not direct or control it. that is unless the core business is IT. For example, Intel's core business is technology, but a bank has a core business of finance not IT.
Where I disagree with Col is that IT is not just services, but it is PRIMARILy services in nature. If I work for a software provider IT isn't only services it is also product. See? However, the services side is the greater presence of IT in the market.
Hope this made sense.