From the Over the Air website:
The Nokia Premium Developer Programme provides high value tools & support to help you be more productive, develop quality apps and enhance your Windows Phone development experience. Get this package of benefits worth up to USD $1500 for free if you commit to using the Windows Phone platform during Over the Air.
The joint team are interested in hacks (in the traditional sense of 'doing something cool' with technology) based around Nokia's Music API, although that's not a restriction on using any other feature in the hardware or available API.
We'll keep an eye on the results and keep you abreast of any interesting apps that are developed at the event.
If you want to attend the event, it is free (with a suggested donation of £5 to Station X and Bletchley Park) and the details can be found at Over The Air.