Just as you'd expect, Apple's Online Store in the United States and around the world has been taken offline ahead of today's iPad and Mac media event. This is Apple's standard modus operandi: the company always takes the online store down ahead of major press conferences and important events.
Visiting the store yields the message “We'll be back. We're busy updating the Apple Store for you and will be back soon”. Typically, the store refreshes with new products right after the event has wrapped up so today should be no different.