Is there a way to search within the Google archived newspapers?
The Google News Archives has evolved over the years. Google has worked with newspapers to digitize materials via the News Archive Partner Program. There are currently no plans to scan additional newspapers. The date to which these newspapers go back varies by newspaper, but many go back to the mid 19th century, and some even earlier.
As of this writing there are basically two ways you can search the news archives: 1) Using the Archives search box or 2) starting with regular Google. For more on Google, Google Books, Magazines, News Archives or Google Scholar, see the links below. As for apps, it should not be necessary, but a brief search should no apps dedicated to that function.
1. Go to Google News Archives (http://news.google.com/newspapers) and use the search box above the newspapers. Search using the same techniques you'd use for regular Google, such as parenthesis to create a phrase search, and so on. For example "pearl harbor"