HathiTrust Digital Library is a digital preservation repository and highly functional access platform. It provides long-term preservation and access services for public domain and in copyright content from a variety of sources. Some early journals including: The Asiatic journal and monthly miscellany (various titles from 1700s to early 1840s). Worth exploring.
https://www.hathitrust.org
The Internet Archive has a vast range of freely available digitised material, much of which is useful to family historians including historical books, newspapers, magazines etc. It also includes many published parish registers.
http://www.archive.org
Search newspapers available online.
http://news.google.com/newspapers
This page has hundreds of links to online historic newspaper archives from around the world.
http://en.wikipedia.org/wiki/Wikipedia:List_of_online_newspaper_archives
This site has links to digitised newspapers from around the world.
http://icon.crl.edu/digitization.htm#E
