This is the list we've found so far. As and when we find other places to 'ping too' they'll be added here.

To add to movable type 3.2:

> go to settings
> click on 'switch to advanced settings' on the top right hand corner of your page
> go to 'new entry defaults'
> towards the bottom of the page you will see a text box with 3 check boxes, unticked
> tick those
> copy and paste the links below into the text box and save your settings.

To add to movabletype 4.0:
 
> preferences (top nav)
> blog settings (top nav)
> web services (side nav)
> look for 3 click boxes showing google, technorati and blogs
> make sure they are clicked on
> copy and paste the links below into the text box

Easy !

http://blogsearch.google.com/ping/RPC2
http://rpc.blogrolling.com/pinger/
http://rpc.pingomatic.com/
http://topicexchange.com/RPC2
http://www.blogpeople.net/servlet/weblogUpdates
http://xping.pubsub.com/ping/
http://api.feedster.com/ping
http://api.moreover.com/ping