Google Blog Search is now accepting pings and republishing the updates it observes. You can submit an update using XML–RPC or REST, similar to other blog services and easily added to your weblog’s ping configuration.
RPC endpoint: http://blogsearch.google.com/ping/RPC2
Google publishes the last 5 minutes of ping activity in its changes.xml file. It is possible to receive pings of different recency by adding the last parameter to your request with a number of seconds between 1 and 300.
The new service is a change in Google’s view of the web, accepting the value of fresh index content within minutes instead of waiting for the regular polling schedule.