Windows Live Writer is a free application designed by Microsoft which enables desktop blog publishing. The software is easy to use and features a user friendly GUI. Download, add your blog to WLW, configure (there is a wizard) and you are good to go. You can just type your blog entry in WLW and format using a WYSIWYG (What You See Is What You Get) editor. You don't even have to open a web browser to publish a blog entry. It's all integrated. (Finally, something Cool from Microsoft.)
We at FILEnetworks have been using it for a while and it's been a smooth operation so far. Keep this in mind though : It's still beta. However during our usage, we found no critical bugs which are usually present in beta releases.
WLW currently supports following blog services:
WLW can be downloaded from the official blog. WLW official blog is located at http://windowslivewriter.spaces.live.com/
Bottom Line is that this app can be a real time saver if you are a hard core blogger.