A blogging client acts like a word processor, and because it is located on your computer’s hard drive, you can write posts even when offline. Blog clients also make it possible to update multiple blogs through a common interface.
There are many of these programs available, and one of them is Zoundry Raven. Raven is an open-source client, and it supports all of the popular blog formats like Wordpress or Blogger and is a good alternative to popular Windows Live Writer.
via makeuseof.com
If you're looking for a desktop client to support your blogging efforts, this could be it.