Another thing I used in my classroom was twitter (http://www.twitter.com/).
I used this site as a diary for my students. They had to write in it once a week. The purpose was to have them produce English writing once a week. I did not check their grammar, subject, or anything else. If they asked me personally, then I did, but the purpose was for them to write in English a little bit a week.
One of the best things for this site is that it is dated, so you know who wrote what and when.
At the beginning of the semester, I gave out my students a handout:
At the end of the semester, my students handed in the sheets to me. I would go online, into their twitter account, and check to see if they did the writing.
This is the second semester I did this and I will continue to do so in the future.
Other ideas I have are:
1. Giving them weekly topics to write about. Short questions that require short answers.
2. Use this as a mini-blog for low level students or grade school students.
Summary, twitter is an excellent way for students to produce writing in English on a weekly (daily) basis. Even though it may be only 140 characters long, producing a few sentences is better than not writing at all.
The feedback I get from my students are positive and does improve their writing skills.