Subtitles

I don’t take it there’s a built-in way to add subheadings / subtitles to posts, is there? If not, is it something the WordPress development team is planning? If not, what’s the best plugin for such a feature? I’m good with coding and PHP so I’d like something I can toss in my template on my own and easily customize.

My only worry is that WP will implement the feature and my subtitles from the plugin would become useless.