The Google Blog Search Pinging Service API allows users who frequently update their blog to programattically inform Google Blog Search about changes to their blogs. Blogging provider admins can also use this API to notify Google of changes to blogs on their platform(s). To set up automated pinging of Google Blog Search, create either an XML-RPC Client or a REST Client which sends requests as noted below. It doesn't matter which method you choose for notification; both are handled in the same way.
http://mah.everybody.org/docs/xmlrpc-url-scheme-rfc
http://www.google.com/help/blogsearch/pinging_API.html