Leaving and re-entering Italy while waiting for the renewal of the visa (Permesso di Soggiorno) – The old rules will become effective from the first of April.

Once again, facilitations to leave and re-enter Italy for visa holders waiting for renewal (those who hold only the receipt testifying that the application for the renewal of the visa has been submitted), are un-understandably destined to expire.
The Ministerial Memorandum from the 12 December 2007 stating that visa holders waiting for renewal are allowed to cross terrestrial, maritime, or aerial borders within the Schengen area is effective only until the 31 of March 2008.
From the first of April the old rules will become effective. Therefore visa holders waiting for renewal can exit and re-enter Italy if:
  They cross the same checkpoint at the border when going out and when re-entering the country
  Their journey does not entail any transit across any of the Schengen countries

Go to the practical instructions on this topic