Google has just launched a Google Blog Search Pinging Service. According to the Google Blogsearch FAQs – This service is a way to inform Google Blog Search of weblog updates. These updates are then published and shared with other search engines to allow them to discover changes to your weblogs. The FAQs also mention that Google currently monitors other pinging services and will continue to do that. However pinging Google directly will potentially reduce latency when crawling your blogs.
The Google Blog search service should ideally be pinged each time your blog changes or is updated. This can be done manually at http://blogsearch.google.com/ping or automatically using their API. Google also mentions that a lot of commercial blogging providers may already be pinging Google Blog Search.
Lastly they have re-assured the blogging community that they will continue to monitor other pinging services like before.