Developers can now register to participate in Windows Marketplace for Mobile to develop, test, certify and distribute their Windows Mobile applications via the Windows Marketplace for Mobile, Mobile team blog.

Steps for developers?

-REGISTER NOW. Developers can submit their complete profile information and take the first step in registration.
-Follow the Windows Mobile Developer team on Twitter @wmdev, Facebook and YouTube.
-And, stay informed with the latest development tools on the Windows Mobile Developer Center on MSDN.
-More info: FAQ