Fee-based:
- Ancestry.com
- GenealogyBank's Newspaper Archive
- NewspaperArchive.com
- Newspapers.com
Free:
- Library of Congress digital collection
- Historical Newspapers Online-list of links--at Penn Libraries. A great set of links.
Don't worry...we're not going to start running lists of links on this site. I usually post websites that are new to me at my Search Tip of the Day blog.