Federation of East European Family History Societies (FEEFHS)
A large U.S. organization loosely connecting many genealogy groups interested in eastern Europe. Has a very large database of records of family events (births, deaths, marriages) as well as a wealth of maps and societies all over the world. All of the text on the site can be easily searched by keyword.

Society for German Genealogy in Eastern Europe (SGGEE)
A Canadian based organization covering many areas in Europe not well supported by GRHS or GGD. The maternal side of my direct family line comes from areas they cover (Volyhnia & Prussia).

Cyndi's List Of Genealogy Sites on the Internet
This site has a huge collection of links to genealogy related sites. Organized by topics. Maintained by one person, Cyndi Howells, but her energy and organization has made this an award winning site. Definitely worth a visit.

Eastman's Online Genealogy Newsletter
Well known genealogist Richard Eastman puts out a weekly newsletter of insights on Genealogy.