Auto-generate title from post content

I’d love to be able to just post content to my blog and have the post title auto-generated from the first, say, 50 characters of the post content. I’d love for the post title to be generated and preserved in the database as a post-submit operation. I’ve looked around and have not found something that might be able to achieve this.

Does anyone know of something that might help me here?

To summarize, whenever I post (via the dashboard, via iphone client, via email etc.) I would like for an operation to execute to ignore whatever title was associated with that post (if provided) and simply generate the title from the first few (non markup) characters of the post.

It would make my day!