This article should be the first mandatory reading in usabillity 101!

Paul Sherman wrote a fantastic discussion highlighting the importance for usabilty practitioners taking a long term cultural view of the organisations and projects they work on.   

By empathising with the IT department’s culture and understanding why they do things the way they do, you can become a ‘change agent’ within the business.  If you understand how to clearly and accurately communicate with IT in a way that the business also understands then you will be able to be the natural liaison and hopefully become invovled at the beginning of every project instead of at the end when it’s too late.

Practically, this means that by working toward a ‘better outcome’, rather than the ‘perfect solution’, you will win incremental battles. Over time I’ve noticed that, with some patience, this approach results in successful long term relationships and dramatic return on technology investment for my clients.