Tuttoricamo.com is an Italian which houses quite a bit of information on traditional styles of Italian embroidery including Assisi, Deruta, Perugian, Sicilian Drawn Thread and Palestrina Embroidery. The site is in Italian and English.
The site houses historical articles, instructional material on how the various types of embroidery are done and a list of common names for stitches are in English and Italian. Also free designs and patterns are published each month.