Sites to ping your weblog
Pinging with either Movable Type or with WordPress is pretty easy to do but the tough part is knowing where to ping. Here are the sites that I ping:
http://api.my.yahoo.com/rss/ping?u=http://(your weblog address)
For the most part these seem to work although I occasional get some errors back. Remember to register your weblog at http://my.yahoo.com before you put your address in there and while you are at it go and register at lots of weblog sites as well. Robin Good has created a great list of sites to register your blog with.