Heres a bunch of fun reading if you have a lot of free time! US Military field manuals. They recently published this one:

] FMI 3-07.22. Counterinsurgency Operations 1 October 2004
] (3 MB PDF file)

This book covers new tactics being employed in Iraq and Afghanistan.

Other interesting books include:

] # FM 24-18. Tactical Single-Channel Radio Communications
] Techniques. 30 September 1987.
] # FM 24-33. Communications Techniques: Electronic
] Counter-Countermeasures. 17 July 1990.
] # (C)FM 32-20 Electronic Warfare (EW) (U)
] # (C)FM 32-30 Electronic Warfare, Tactics of Defense
] # FM 33-1 Psychological Operations August 1979
] # FM 34-1, Intelligence and Electronic Warfare Operations
] 27 September 1994. [superseded by FM 2-0]

Army Intelligence and Security Doctrine