Hi Nargeskamali, about your question - I ask someone contacts of teachers using blog on classes but probably it will be more on high education. next week hope to be able to send information about it. Meanwhile, about the online environments on education maybe you like to check the web site from Professor Stephen Downes that publish very important matters on education see the site:http://www.downes.ca/ see you.  

Hi Nargeskamali - found today this blog from a English Teacher that uses blog in her classes. Has some very interesting thoughts about students experiences and interactions during bloging. i'm still waiting for the other contacts, then hope to tell you more. for now hope it helps: http://myam-rimach.blogspot.pt/ See you

Hi Nargeskamali, in response to your question I've seen blogging help my kids (who are aged 6-7) by it focusing in on punctuation as well as developing a 'voice' to their writing with features such as BIG LETTERS for impact and looonnnggggg words for effect.  Hope it helps... (they've started doing that too!).