Sites that have more than one topic dedicated to Ultima

http://www.moongates.com/

A very well done site with several useful sections.

History:
http://www.moongates.com/History/default.htm

Festivals
http://www.moongates.com/Festival.htm

Music
http://www.moongates.com/music/default.htm

Library
http://www.moongates.com/Library.htm

Ultima: Aiera, an Ultima Project archive site
The Ultimate Ultima blog, an excellent source of current ultima news and resources.

http://www.ultimaaiera.com/

Ultima: The Reconstruction

A site dedicated tracking progress of Ultima Remakes

http://reconstruction.voyd.net/index.php?event=news

Ultima Worlds - Bootstrike.Com

A site with many usefull sections, as well as other games and topics.

http://www.bootstrike.com/Ultima/index.html