Fourmilab Switzerland
John Walker: 1 Thessalonians
The actual Biblical text of 1 Thessalonians taken from the King James Version of the Bible.
Other
Ray Stedman: Adventuring Through the Bible
"Adventuring Through the Bible" is a comprehensive guide to the entire Bible with Bible commentary. This site is an excellent place to start if you are new to the Bible and/or have questions about evangelical Christianity.
Bible.org
1 Thessalonians: Introduction, Outline, and Argument
An excellent in-depth look at 1 Thessalonians. Includes background information, religious significance, and major themes of 1 Thessalonians along with a detailed outline of the entire book.