tell application "Yojimbo"
	set _items to selected items of browser window 1
	if (_items is {}) or (_items is missing value) then return
	set _note to item 1 of _items
	if class of _note is not note item then return
end tell

tell application "MarsEdit"
	set _post to make new document
	set body of _post to contents of contents of _note
	set title of _post to name of _note
	activate
end tell

Click here to open the script directly in Script Editor. Save it in ~/Library/Scripts/Applications/Yojimbo and you’re ready to run.