Game Editors

CGoban 3
Includes an editor for SGF go files and a client for the Kiseido Go Server.
http://www.gokgs.com/download.xhtml

Complete Goban
Go program for Unix and X11. Local, internet or modem play, as well as .SGF-compatible record and replay.
http://www.igoweb.org/~wms/comp/cgoban/index.html

Drago
Windows freeware. Features include handling of multi game SGF files, playing against GNU Go, replaying problems and games, and prints and exports to various file formats.
http://www.godrago.net

The Go Assistant
A set of tools for the serious go player, including a variations editor, IGS client subsystem, and a full OLE server.
http://www.airsltd.com/goassistant/

Go for PalmOS
An interface for playing and replaying Go on a Palm. Uses SGF format.
http://www.lirmm.fr/~kiss/Go/index.html

Goban
Free software to play go on Mac OS X against the computer or over a network. Includes Universal binary.
http://www.sente.ch/software/goban

GoodShape
Small java Go applet for showing games, variations and problems.
http://playgo.to/gs/about.html

Jacqueline Go
Java Go program that also can be used as a frontend for GNU Go. Supports SGF and GTP.
http://www.informatrix.ch/go/index.html

JavaGO
Freeware java go applet for editing games.
http://javago.free.fr/

JText2Sgfs
A utility to extract SGF game records from a single text file.
http://www.gungfu.de/go/coding/JText2Sgfs/

MultiGo
A pretty and complete SGF viewer/editor for the Go games records.
http://www.ruijiang.com

TI-Go
Two programs for the TI-89. One to record games in Ishi format, the other to read them back and display them.
http://www.nittka.de/gosoft_e.html