Textastic is a magnificent text editor for iOS. And I have just discovered that it also handles Markdown very graciously.

Moreover, its perfect integration with Dropbox allows me to download a Markdown file, edit it, and re-upload it on the server with the push of a button. This last possibility expands to its full potential now that I am trying a Dropbox+Markdown+Scriptogr.am posted blog. I can nearly do everything in Textastic except push the Synchronise button on the Scriptogr.am dashboard. I hope that this part will become automatic one day, too.

Textastic understands many language syntaxes and you can expand the set using modules from Textmate.