Drafting the plan.. where to begin?

As an ITIL programme is being included in our proposed IT strategy I've started drafting a plan. Just where does one start when introducing ITIL? Assuming that you are familiar with what ITIL is and the benefits of each process then I think identifying points of pain is a good start. Then you can identify which processes will help you eliminate those. They may not be 'quick wins', but as long as they make a REAL difference then they will help secure the CONTINUED buy-in needed for the other processes.

In our case, with three authorities coming together for IT service provision we have 3 major pain areas:
- High number of incidents and not enough staff to resolve them all within SLAs
- No clear delineation of service support roles and responsibilities across the 3 councils so calls are frequently assigned to the incorrect team which contributes towards breached SLAs
- Seemingly innocent 'It's a 5-minute job' changes made to shared council network infrastructure can create unexpected issues

Before I reveal which processes I'm including in the initial programme; given the information above, which do YOU think would help us and why? Answers on the back of a postcard... (not really, just use the comments!)