By Faith.  A web magazine of the PCA: http://byfaithonline.com/

Reformation 21: http://www.reformation21.org/

Charles Haddon Spurgeon archive: http://www.spurgeon.org/mainpage.htm

Reformation Theology: http://www.reformationtheology.com/

Ligonier Ministries: Dr. R.C. Sproul: http://www.ligonier.org/rym.php

Truth For Life: Alistair Begg: http://www.truthforlife.org/site/PageServer
-also-
http://www.parksidechurch.com/

First Presbyterian Church of Jackson Mississippi: Ligon Duncan, Derek Thomas.
http://www.fpcjackson.org/index.html

The Alliance of Confessing Evangelicals: http://www.alliancenet.org/

The Bible Study Hour.  James Montgomery Boice: http://www.alliancenet.org/CC_Content_Page/0,,PTID307086%7CCHID560458%7CCIID,00.html

Grace To You ministries. Dr. John MacArthur, Jr.: http://www.gty.org

The 'Bible Answer Man'.  Hank Hanegraaff: http://www.equip.org

Christ Fellowship Baptist Church.  Steven Lawson: http://www.cfbcmobile.org/

Desiring God.  Dr. John Piper: http://www.desiringgod.org/

Online Bible Resource: http://www.biblos.com