Centro Studi Italiani Online Classroom
From the site:
"The Italian Electronic Classroom! is a project of Centro Studi Italiani, aimed at providing free on-line, useful information on difficult aspects of the Italian language to students, teachers, translators, writers. This is a work in progress. Periodically we will add new pages on topics covering grammar, vocabulary, pronunciation and so on. Visit our site again and send us your suggestions!"