Blizzard has announced that the real-money auction house (RMAH) for Diablo III has launched in North America. The US dollar, Mexican peso, and Australian dollar are all currently supported, with support for the EU region coming soon.
Using the RMAH requires that a player has a authenticator attached to their account. In addition, if a player decides to use PayPal, then they must also activate the Battle.Net SMS Protection feature.
Only weapons and armor are available on the RMAH at this time, with commodities being added later. Further information about Diablo III's new system can be found here.