Sega

Act Select
Sega Sonic's fansite (written in Japanese and English). Sega's replica fonts (60 kinds), Sonic's history, Goods collection's photo, and Short Flash animation.
http://www.clavis.ne.jp/~sonic/segasonic/

Gamegear.nl
Contains hardware and software information of Game Gear, trading, images and some links. Also has collection listings of other Sega systems.
http://www.gamegear.nl/

The Rockin'-B
Homebrew development for SEGA Saturn and VMU. Includes games, demos, emulators for gamers and libs, sourcecode, and tools for developers.
http://www.rockin-b.de/

The Saga of Sega, Rise and Fall
Contains information about the past and history of Sega.
http://www.geocities.com/markjenkins666/sega.html

Sega Europe
Official site with news, game information, and console information.
http://www.sega-europe.com/

Sega Forever
Contains reviews, downloads and guides.
http://www.emulationzone.org/sections/segaforever/

Sega.com
The official Sega website.
http://www.sega.com

SegaFans
Coverage for Dreamcast, Sega Saturn, and Genesis. Includes reviews, screen shots, movies, and where to purchase games.
http://www.classicgaming.com/saturn/

Tim's Sega System Tech Site
Offers information for diagnosing and repairing several Sega systems, such as pin-outs, voltage and polarity, making an RGB monitor, and cleaning cartridges.
http://www.mrvfone.com.au/sega/