I moved blogs from one server to another some time ago, and luckily I was using ecto to post, so had an archive of the posts on my computer.
I wrote an AppleScript to move a post from one server/account (ecto calls them personalities) to another, and popped it into the ~/Library/Application Support/ecto/scripts directory, set up a shortcut key, and then it was just a matter of opening a post, pressing the key, and it posted the old post to the new server.
Some posts caused ecto to crash, but I could live with that.
Anyway, here is the script:
tell application “ecto”
set _draft to document 1
tell _draft
set _date to entry date
set current personality to “Blogsome”
set entry date to _date
do post
end tell
end tell
