Google Blog Search (beta) is definitely a better way to perform a search on blogs. The search results include blogs that publish a site feed in any format and automatically pings an updating service.
Google Blog Search is available via http://blogsearch.google.com and currentlydisplay search results that are older than June 2005. Google is making effort to include older posts in the search. So stay tuned.
Such a move will sure prevent many execs and programmers from Microsoft and Yahoo from sleeping well. As usual, they will possibly follow with similar blog search.