Dimox

Live post preview on “Write/Edit post” page of WordPress admin area using jQuery. If you don’t like WordPress built-in Visual Editor (because it puts a lot of unnecessary tags or by any other reasons), but you want to have live post preview like in Visual Editor, this plugin may be useful for you.

jQuery Post Preview

Live post preview on "Write/Edit post" page of WordPress admin area using jQuery.

Christopher Finke

Inline Preview is a plugin for WordPress that adds a live preview of the current post next to the post editor instead of opening the preview in a new tab.
Problem: When creating a post in WordPress, previewing your post in a separate tab can be slow and/or complicated.
Solution: Show the preview right next to the editor.
It’s just an idea I’m playing with for streamlining the post creation process, and if it feels familiar, it’s probably because it is: through version 2.1, WordPress contained a preview iframe at the bottom of the post editing screen, but this is a more elegant implementation.

Inline Preview

Inline Preview adds a preview of the post you're writing next to the editor when you click Preview (instead of opening it in a new tab).

jQuery Post Preview vs Inline Preview