A statement from Apple provided to The Loop reads as follows:
Apple also set up a new page on its website detailing all of the ins and outs of the replacement process. Some quick facts to keep in mind include that the replacement program is already live for folks in the U.S. and Canada and will go live for consumers in other countries beginning on May 2.
Apple today launched a program to replace the sleep/wake button on a small percentage of iPhone 5 models where the button may stop working or work intermittently. Apple will offer the service free of charge to iPhone 5 customers with models that exhibit this issue and have a qualifying serial number.
Further, the entire replacement process will be carried out Apple Repair Centers and affected users can expect the process to last anywhere from 4-6 days. In the interim, affected users can receive loaner iPhones from either Apple retail stores or authorized Apple service providers.