WinMGT, by Hui Huang, is an excellent sgf file reader. It's the program used to create Kogo's Joseki Dictionary.
WinMGT is for Windows 98, ME, NT, 2000 and XP. WinMGT does not work with Windows 95.
This page offers download of the last version of WinMGT; version 0.87. Though it has a low version number, WinMGT is a mature product. WinMGT version history.
Instructions: Download the zip file. Inside the zip file is an executable installation file.
If you are a registered user of WinMGT, email kogo with proof of registration, and you will be emailed the registered version (which will still require you to input your registration information).