Markdown Edit - The Markdown Editor for Windows
Pastebin.com - Pastebin.com is a website where you can store text for a certain period of time.
Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
hastebin - Pad editor for source code.
Minimalist Markdown Editor - This is the simplest and slickest Markdown editor.
GitHub Gist - Gist is a simple way to share snippets and pastes with others.