Here are some of my favorite sites:
Horizoncentral.net This is my home church. At Horizon Central, we go through the Bible, verse by verse. Many of the teachings are available for download on this site.
Redeemedscoundrels.com is the website for Good Messengers. Good Messengers is a local organization of street evangelists in the greater Indianapolis area. There are a lot of good articles on this site as well as a “good person test” that can help a person see his/her need for a savior.
Blue Letter Bible is a great site with lots of Bible study helps.
T4T Online is where you will find the book T4T, a Discipleship Re-Revolution. This book is highly recommended by me and anyone I know that has read it. This book bridges the gap that has come between discipleship and evangelism. There are also a lot of tools available on this site.
Living Waters is the ministry of Ray Comfort and Kurt Cameron. This site has lots of evangelism tools.
Mark Cahill Ministries is where you will find several good books written by a man that lives out his faith by making evangelism a daily way of life. There are some great resources for helping you share the gospel with others.
E-Sword is FREE Bible software that gives you great study materials including several translations of the Bible in many different languages as well as text from the original languages of the Bible. There are also integrated commentaries and dictionaries as well as other useful tools. I believe this is the best free software available and it rivals many very expensive software libraries.