Update: iTunes services appear to be coming back online, though it make take some time to restore services for everybody and all devices.
Original story follows.
The iTunes Store and App Store are currently down for some people in some parts of the world, taking with it a bunch of the iTunes ecosystem. You aren't going to be downloading any movies, music, or TV shows, you won't be streaming off iTunes Radio, and your Apple TV won't even let you watch any such items. Poof, they're gone. iMessage, FaceTime, and other Apple web services don't appear to be affected.
Apple's system status tracker is currently showing green across the board, though if this outage persists much longer we expect that we'll be seeing some red popping up on there.
Attempts to access iTunes on an iPhone or iPad are met with the message of "Cannot connect to iTunes Store", whereas iTunes on a desktop gets "Item Not Available: The item you've requested is not currently available in the U.S. store." (that item being the store itself). Apple TV, well, your stuff just vanishes.
We'll let you know when the store is back up — in the meantime, how are you dealing with iTunes being down?