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 sites 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