Slovo - Information on how to set up PCs for Slavic and Cyrillic languages, covering a variety of operating systems. In English, German and Russian. - http://www.slovo.info/
Russian Cyrillic Helpers - A variety of tools to aid inputing cyrilic characters, plus transliteration and keyboard guides. - http://www26.addr.com/~y/rus/
Russify Everything - How to adapt various systems and software for use in Russian, including details on Russian character encoding systems. - http://www.siber.com/sib/russify/
KOI8-U Ukrainian Character Set - Ukrainian variant of KOI8-R and ISO-IR-111. Includes tables and links to other related Ukrainian and Russian resources. - http://cad.ntu-kpi.kiev.ua/multiling/koi8-u/index.html
Fingertip Software: ISO 8859-5 table - Table for this Cyrillic code set, also known as Soviet GOST 19768-74. - http://www.fingertipsoft.com/ref/cyrillic/iso88595.html
Cyrillic in different encodings - Covering UCS-2, UTF-8 Little-Endian, KOI8-R, Win-CP1251, DOS-CP866, ISO-8859-5, Mac-Cyrillic, KOI8-U, ShiftJIS and Unicode Big-Endian encoding systems. - http://www.dimka.com/ru/cyrillic/
KOI8-R Russian Character Set - Information relating to the KOI8-R Russian character set. Includes tables, software information, keyboard layouts and many links to related resources. In English and Russian. - http://koi8.pp.ru/