Movabletype has a facility where you can 'ping' various blog directories and search engines everytime you upload a new post. if youre doing Online PR, then letting the right istes know you have made another contribution to the blogosphere is important.

Instructions:

One of the problems with movable type is finding good plugins.... so here is a good place to have a root around
http://mt-hacks.com/

I've been working on an enterprise level movabletype setup with a very good design company called studiolift. These were the plugins they used on a MT 3.4 install