On Ubuntu OS, there is a tool named "Blogilo" that could help you write blog just as the Windows Live Writer does.
Install Blogilo
sudo apt-get install blogilo
Configure Blogilo
After you have successfully install the blogilo, you could start add a blog from here: "Blog" -> "Add Blog...".
For example, here are some requirement when I configured my cnblog account:
Blog/Homepage URL: the format just as following “http://www.cnblogs.com/Blog名/services/metaweblog.aspx”
Username: <username>
Password: <blog_password>
Advance->"API" : MetaWeblogAPI
Reference
http://www.cnblogs.com/wwang/archive/2010/10/28/1863746.html
http://www.cpplive.com/html/230.html