COLDIC is an integrated lexicographic platform for creation and management of electronic lexica. Generates itself automatically from a DTD with the database schema and provides human interfaces (query and insert tools) and machine interfaces(webservices)
Learner lets you teach a computer in plain English. You can teach both simple statements and ways of reasoning. Learner will ask you follow-up and new questions. See http://teach-computers.org (not yet active).