MacRumors received a copy of the note that was sent to European distributors regarding the discontinuation:
[indent]As of March 1, 2013, Apple will no longer sell Mac Pro in EU, EU candidate and EFTA countries because these systems are not compliant with Amendment 1 of regulation IEC 60950-1, Second Edition which becomes effective on this date. Apple resellers can continue to sell any remaining inventory of Mac Pro after March 1.
Apple will take final orders for Mac Pro from resellers up until February 18th for shipment before March 1, 2013.
Countries outside of the EU are not impacted and Mac Pro will continue to be available in those areas.[/indent]
IEC 60950-1 is a fairly standard set of electronic safety requirements, and its not clear yet how the Mac Pro violates the new standards. Of course, that doesn't preclude Apple from revamping the Mac Pro's internals to meet this new regulation — after all, we just learned yesterday that Apple is making a minor component change to the current Apple TV. There's also the chance that Apple could use this occasion to introduce a fully-refreshed version of the Mac Pro. However, given the lack of attention the company has given its professional line of machines — and the company's focus on its "post-PC" lineup of devices — there's no telling if or when this refresh would happen. Apple did say that it planned to update the Mac Pro sometime this year, and the upcoming shipment ban seems as good a time to do so as any. We've reached out to Apple to confirm this news and will update this post with any new information we hear.
Update: We can now confirm that the Mac Pro will be discontinued as of March 1st — resellers are able to continue selling the computer past that date, but no new shipments of the current Mac Pro will go out in Europe. Given the plans for a Mac Pro refresh later this year, as originally reported by The New York Times last summer, it seems Apple decided to wait for that rather than make minor changes to the Mac Pro to meet these new regulatory requirements.