Windows store is a store to find metro style apps. It promises best economics for developers. Revenue sharing starts at 70% for new apps, it jumps to 80% once the app makes $25,000.
There will be local currency payments and settlements.
People will be able to discover your apps through search engines.
Windows app store will be available when Windows 8 Beta is released which is likely to be late Feb 2012.
Learn to build Windows Metro Apps here http://msdn.microsoft.com/en-us/windows/apps/