Ok.. So is this a DoS or not?

Source

A 21-year-old man from St Neots has been arrested after the main switchboard at Cambridgeshire police HQ was jammed by thousands of calls on Friday.

Concerned callers rang the Huntingdon-based HQ after receiving an email informing them that £399.99 would be taken out of their account to pay for an iPod music player they'd supposedly ordered.

The email also advised recipients that they should call the number listed in the email if they had any queries. The snag was that the number did not belong to some ecommerce outfit, but to Cambridge Police HQ. Its phone lines were jammed.

At the height of the deluge the HQ received more than 500 calls an hour as callers phoned to find out why they were being billed for something they hadn't ordered.
Pretty nifty I guess if you want to get back against telemarketers. But man. Talk about an interesting side effect of an email spoof.

Another Source