Like us many Windows Live Writer users may have received a alert when you opened a fresh copy of WLW, saying that WLW will expire in certain days.
Quote from the blog:
On Monday (September 1, 2008) the Technical Preview of Writer started erroneously triggering expiration for October 1, 2008. We have fixed the issue that was causing the false expiration. While the Technical Preview of Writer will not expire on October 1, you may still see this notification again.
When you see this notification, click the Ask Me Laterbutton and you will be able to continue using Writer without any change. We apologize for any confusion this may have caused.
So you do not have to worry about your Windows Live Writer expiring, carry on blogging as you would normally, we assume that a new mandatory update will be pushed out shortly to fix this issue and stop WLW from expiring on September 30th.