There is a site called www.pprune.org (professional pilots rumour net) which is a huge site catering for worldwide aviation things. It has a mil forum, frequented mainly by RAF types. Its rather dull now as it consists of dress wearing whining crabs talking about makeup and lack of expenses for staying in hotels whilst overnighting in Bangkok.
Most of those on pprune are just sad men (not many women pilots in the RAF) who love a bit of self-congratulation and self-admiration. A few interesting topics if you're interested in learning a bit about aeronautical engineering, but as soon as you mention the Army you will be mocked.