One of my favorite news search tools, Canada's RocketNews, has added a couple of new features to make searching and limiting to weblog content a bit easier.
First, you'll notice a pull-down menu next to the search box on the RocketNews homepage where you can limit your search to either news sites (over 11,000) or weblogs.
Second, on search results pages you're now given options (after selecting Advanced Search/More advanced settings) to limit your search by weblog category and location. RocketNews staff manually reviewed each blog in their database and then added the metadata to make category and location searching possible.
You can also begin your search using the advanced "weblog search" interface by going to this page.