Magic the Database  
   Freeware application database program for game enthusiasts and collectors. Designed to track card collections, create and build decks. Search queries and query scripting capability.
   http://www.magicdb.net

Blue Wizard  
   Includes survey, screenshot, help, and updates for the Blue Wizard deck creation and management software.
   http://home.hetnet.nl/~fam-wehrens/bluewizard/

Magic Analyst  
   A sophisticated freeware database for MtG deck builders and collectors. The Magic Analyst is a virtual library of all the cards ever printed, making it easy to catalog and appraise your collection, find key cards, and construct better decks.
   http://www.gmks.com/MAGIC/Analyst.html

The Magic Workstation  
   A freeware package designed to enable online play of Magic: The Gathering. It also includes features to assist with deck construction and card inventory.
   http://www.magicworkstation.com/

MTG Studio  
   A freeware application for deck construction, multiplayer, and net draft.
   http://www.palmroot.com/

The Complete Magic Database (CMD)  
   CMD is a multi-functional information system for the collectible card game Magic: The Gathering. Detailed information on every card and serves as a tool for planning effective decks, and tracking inventory. (Requires Javascript)
   http://cmd.reinkvist.dk/

Spellbook  
   Build decks, search for cards, inventory cards, check errata and rulings, print proxies, import card art. Freeware download for Windows and Macintosh.
   http://members.empowering.com/gwfran/Spellbook/

Magic Spellbook  
   Freeware program containing information about each and card and its abilities. [Windows]
   http://www.magicspellbook.com