Want to ping Google Blog Search manually to tell them you have updated your blog or feed? You can do so at http://blogsearch.google.com/ping. Want to automated it? Build it in to your code using the Pinging Service API. Have more questions, see Google About Pinging Service.
You can see that I had some issues with Pinging Google Blog Search.
I think Google doesn't support xmlrpc.com/weblogsCom standard. But I am not a 100% sure.
DigitalPoint Forums explains;
I don't ping pingomatic anymore, just feedburner and google, feedburner pings all the others for me.
Forum discussion at DigitalPoint Forums.
This article was written the night before, and scheduled to go live the following morning.
Update: Seems to be working now.