Sinclair Spectrum Game Data Formats
   A repository for the collection of game data formats for old Sinclair games.
   http://www.icemark.com/dataformats/index.html

XeNTaX's MultiEx
   MultiEx allows you to extract and import files from over 90 game data formats (including HOG, PAK, WAD, and SFX).
   http://www.xentax.com/html/multiex-main.htm