Here is a quick little mini-plugin that I wrote to help me in the development of the next version of MultiBlog. Comment Callbacks establishes two callbacks for the comment system of Movable Type:
CommentCallbacks::PostCommentPostwhich is called right after a comment is first postedCommentCallbacks::PostCommentApprovewhich is called right after a comment is approved
If a comment is approved when it is posted (for whatever reason, be it no comment moderation, TypeKey authentication, etc.), both callbacks are called in the order above.
To install, download one of the following files, unpack it, and place comment_callbacks.pl in your plugins/ directory.
Thanks David, this works great. Perfect solution to the exact problem I was having earlier tonight!
You read my mind.