The price is a SSD harddrive signed by Notch himself and a painting by Kristoffer Zetterstrand.
Here is what Notch posted on his blog a few days ago:
Webhallen Minecraft texture pack competition!Webhallen is a really awesome Swedish hardware/game store that I use privately a lot. The guys running it seems to like Minecraft, and asked us if we could do a competition together, so we did!
Minecraft will very soon feature official texture pack replacement support, and the competition is to make the most awesome texture pack possible for Minecraft!
Check it out: http://www.webhallen.com/minecraft/
First prize is a 180 GB SSD signed by me (yes, on the actual drive!) and an original painting by Kristoffer Zetterstrand, who made all the paintings in the game. The new painting will be added to the game, but you get to own the original.
The official texture pack support is coming soon. It was supposed to be part of the halloween update, but I kind of forgot.. In the meanwhile, PC Gamer wrote an excellent guide on how to install texture packs until this new support is added:http://www.pcgamer.com/2010/09/25/how-to-install-a-minecraft-texture-pack
The competition runs until December 20 (I think..?), and is available to anyone who can receive UPS deliveries.
For further details, go here: http://www.webhallen.com/minecraft/
There are also a price for second and third place. You send your packs to webhalling with the form they have set up HERE.
Join the competition and do something awesome!