This is what I have found out so far for the Spoleto: VINI NEL MONDO 2012 ... any one able to confirm these dates?
June 2 to 5, 2012
It also looks like Saturday June 4th, 2012 is "La Notte Bianca del Vino" the white night of wine. I found this not on their official site but an agriturismo. It is a weekend where you pay a price for a wine glass and a neck pocket sleeve. then you go do different booths trying out their wines. Often there are booths with local cheeses, honey, jams, etc.