I understand Posterous is a YC company, and we're supposed to be all ga-ga eyed about them... but in all honesty the only thing to resurrect your dead blog is you. Not software. Just sit down and write.
The point is that using posterous removes the added effort that 'blogging' seems to be.
By redefining the problem as email, it's much easier to just sit down and write. For example, I had been thinking of tracking my moods for a very long time. Finally, what I did was sign up for posterous and set up a google calendar reminder. All I now have to do is hit reply and type a couple of lines. It's been working great for two months.