Google Blog Search supports pings. If you add posts and your blog supports XML, you can send a ping at Pinging Service. Get to know more about pinging service in http://www.google.com/help/blogsearch/about_pinging.html and about Pinging API at http://www.google.com/help/blogsearch/pinging_API.html
Google Blog Search includes all blogs in their search results, The results are not just from blogger.com but also from wordpress.com and your own host blog.
Tip: To search blogs using blogger.com, you can try using http://blogsearch.google.com/?ui=blg
Other related Posts:
(1) Best Blog Search Tool
(2) Promote Your Blog Easy
(3) Your blog not bringing the kind of visitors you want?