1. Integrating the Win8/Metro Plugin into the games. Iunkn has an excellent blog which documents everything you need to take advantage of the many features of using Win8, e.g. In-Game Purchases, Trial Mode, using the Live Tiles, etc
2. Deploying to the store - This part was quite easy - Microsoft will take you through step by step during the deployment process.
It helps to have a little development experience, as you'll need to make your way around Visual Studio 2012 exp.
The game itself still needs to go through MS's review process, but hopefully it will be in there by Oct 26 if all goes well. Normally it should be a 5 day process, but a ton of apps are going in at the moment.