Yes! You can use a third-party service called Posterous. This does involve giving a third-party service a password to create entries on your blog.
I have instructions on how to set up Posterous to auto-post here:
The design of the Posterous site may have changed in the last six months. The most important part of those instructions is still accurate: how to obtain your Web Services Password.
Instead of auto-posting, look for "New Post via Email".