I missed out on this session by Jon Innes recently. Shame as it looked really interesting. Fortunately though, a version of the slides are available on slideshare.
It's all about integrating usability into the planning and development process.
Slide 21 of Jon's talk says it all really; over time through the development process, your ability to influence a product's design decreases while the cost to make changes increases.
This applies to any kind of 'product' - including basic web design and development. A simple and elegant case for testing your plans and preconceptions.
Repositioning User Experience as a Strategic Process - presentation slides by Jon Innes on Slideshare