The popular and valuable guide, the "Ten Most Common Tower Building Mistakes". Over 500 of these have been mailed out over the last two years and now it's available here.
An Internet reflector (mailing list) called TowerTalk devoted to tower and HF antenna topics is now on-the-air! This is a tremendous resource for first-time builders as well as experienced station owners. To subscribe, send a message with the word subscribe in the SUBJECT LINE to towertalk-request@contesting.com. You can also read the Frequently Asked Questions at http://www.contesting.com/FAQ/towertalk. Thanks to Bill, W4AN (SK), for his assistance in setting this up.
This study is of guyed tower failures and collapses to investigate what a typical tower fall radius would be. He determined that all of the debris would impact the ground within a circle with a radius which would not exceed 29% of the tower height. This is a draft of the study from 1985 by Gunnar Olsen, Jr., P.E. and is many generations of copies from the original so I apologize for the poor quality.