
Apple's System Status page is reporting that some users may be unable to make purchases on the iTunes Store, an outage that started this morning around 10:30 AM Pacific time. This is in addition to issues with Game Center and FaceTime earlier this morning.

Update: Apple claims the issues have been fixed
Update 8:57 PM: According to Apple's system status page and reader reports, the problem has returned, with the iTunes Store, App Store, Mac App Store, and iBookstore all experiencing difficulties starting around 8:00 PM Pacific Time.Multiple Services - 11:28 AM - 12:57 PM - Some users were affected
Users may have been unable to make purchases from the App Store, iTunes Store, Mac App Store, or iBookstore. Users may also have been unable to access iTunes in the Cloud, iTunes Match, or restore purchases from an iCloud backup.
Article Link: Some Users Having Difficulties Making Purchases Because of iTunes Store Outage [Updated x2]