The arrest was announced by the Dutch National Prosecutors Office, who said that the unnamed teenager was arrested by a high-tech crime unit on Wednesday night. While his identity was not released, it's believed he may be one of the IRC-operators of Anonymous, known by the handle Jeroenz0r.
Anonymous has attacked numerous targets, including the Dutch prosecutor's office which is trying
to extradite Wikileaks chief Julian Assange from the U.K. On Thursday, Amazon.com, which kicked Wikileaks off its EC2 service, was attacked. However, the site showed just why Wikileaks wanted to use it as a host: it was too robust to be taken down by the DDoS attack.
The teenager has reportedly confessed to involvement in the hacking. However, considering the organization behind all this, one arrest isn't going to stop the attacks.