A large amount of reading material about biological weapons is available over the net. If you are interested in Biological weapons , I also suggest that you search www.cnn.com and/or www.cbs.com for recent news articles regarding the same. I have included most of these articles in the "News Articles" section.

The material given below is what I think is the best that is available over the internet. If you have any files or links that you think should be mentioned here, please let me know at oncogen@kemates.com .

1) The Bioweaponeers:
    
The MUST read file in this section. This is almost a small book (27 pages) but the file size is very small and it is fast to download owing to the fact that it is in MS Word format.

This article, accompanied by suitable photographs, is a very interesting series of informal conversations between Richard Preston, Bill Richards (the former no.1 in the US Biological weapons program) and Ken Alibekov (the former no.2 in the Soviet program). If you want to hear about it from the horse's mouth, here it is.
VERY interestingly written, VERY highly recommended.

(340 KB, approx. 3 min) Word Format.

2) Dark Winter:

This is an official file which documents the outcome of a mock bioterrorist exercise carried out by the US govt. in July 2001 to test it's state of readiness to such an attack.
Although it would seem boring to read such an article on first though, think again. This article reads like a novel. 

There was a mock president of the US, a mock leader of Iraq, et al.. Rather like reading the script of a very good drama actually.. problem is.. this could happen.

The figures mentioned in this exercise are probably the best estimates we have of how a smallpox epidemic could be expected to spread throughout the world.
Also includes rare color photos of smallpox victims.
Recommended.

(767 Kb, approx 6 min) Adobe Acrobat format.

3) The USAMRIID Medical managment of biological casualties handbook.

If you STILL have difficulty in accepting the very real threat of biological weapons, read this guide to the treatment of patients affected by biological warfare written by an institute which until 1972 produced biological weapons itself.
It is very easy & quite interesting to read (remembering what it says is another thing altogether), and the download size is very small. Read it. Who knows.. maybe it will come in use to you some day.

(378 KB , approx 3 min) Adobe Acrobat format.