The sworn translation is an official translation, the accuracy of which is guaranteed by the translator.
When a legal document written in a given language has to be delivered to the authorities in a country with a different official language, the document has to be translated by an accredited expert, who declares on oath, in other words, swears before the Registrar of the Court or a Notary Public, that the document has been translated accurately.
If a translation that has been sworn in Italy needs to be delivered to the authorities of a foreign country, then the translation also has to be legalised (the Apostille has to be affixed for the countries which signed The Hague Convention of 5th October 1961 relating to the abolition of legalisation of foreign public documents).
Also consult: http://it.wikipedia.org/wiki/Apostilla
See the official documents