MarkdownMail iPhone App

MarkdownMail is the easiest way to compose HTML emails on your iPhone or iPod touch. Based around John Gruber’s popular Markdown markup syntax, you can now send emails with bold text, italics, bulleted lists and more. MarkdownMail will convert your Markdown formatted messages into an HTML message that you can send to your friends, family or colleagues.

I use Markdown on for all my WordPress posts and love it.