The Augsburg Confession – This is the confession of faith based solely on biblical teaching that is the chief symbol of Lutheranism.
Luther’s Small Catechism – For over nearly five centuries, the Small Catechism has served as the basic instruction book for the church bearing the name of the great Reformer, Martin Luther. Its staying power goes beyond love for tradition. The Catechism directs us to clear passages from God’s Word. It distinguishes carefully between the two chief teachings of the Bible: the Law and the Gospel. It also points to the only source for spiritual life, the Means of Grace: the Word and Sacraments.
BibleGateway* (look up any passage in any translation — great resource)
Lutheran Theology Website (articles, papers, and resources compiled by Pastor Jay Webber)
Christian Classics Ethereal Library*
Issues Etc.* (a very sound confessional Lutheran daily broadcast that covers tons of issues)