Sites where you can learn and practise English

Here are some useful sites where you can check and practise grammar structures: http://www.ego4u.com/en/cram-up/grammar
(from here you can also access reading and other resources)
There is also: http://vivquarry.com/wkshts/
e.g. http://vivquarry.com/wkshts/linkwd2.html
and http://esl.about.com/od/writingadvanced/a/wc_addition.htm
but for me the best sites are:
Exam English ✓Free Practice Tests for learners of English

http://examenglish.com/cambridge_esol.php
for lots of free practice material at different levels (more later about this)

and BBC Learning English 
http://www.bbc.co.uk/learningenglish new address
and http://www.bbc.co.uk/worldservice/learningenglish/general/old address (but still active)
you should explore the site. For example:

http://www.bbc.co.uk/learningenglish/english/features/6-minute-english

http://www.bbc.co.uk/worldservice/learningenglish/general/sixminute/

is for listening practice and dictation

http://www.bbc.co.uk/worldservice/learningenglish/language/ is for grammar, vocabulary and pronunciation

Other sites where you can practice English

iTunes U (via iTunes , which you must install)http://www.apple.com/it/education/itunes-u/
video and audio podcasts of university lectures and courses. See how your subject is taught in English. TED (Technology, Entertainment, Design)  
http://www.ted.com/
Fantastic presentations from some of the most innovative people in the world. Watching presentations is a really good way to practice comprehension.

The Purdue Online Writing Lab

http://owl.english.purdue.edu/

Online distance courses (MOOCs – Massive open online course)http://en.wikipedia.org/wiki/Massive_open_online_course
http://www.bdpa-detroit.org/portal/index.php?Itemid=20&catid=29:education&id=57:moocs-top-10-sites-for-free-education-with-elite-universities&option=com_content&view=article
http://www.moocs.co/
http://www.mooc-list.com/

TV Channels

The aim here is to listen and improve your comprehension, stay up to date (so you should also follow the telegiornale in Italian) and absorb some of the language.

BBC

http://www.bbc.co.uk/

France 24 in English

http://www.france24.com/en/

Aljazeera in English

http://www.aljazeera.com/

You can also get a wide range of live TV channels on:

http://www.filmon.com

and shows on:

http://allnewepisodes.com/tvshows/