Here in Swansea (South Wales, UK) we don't have a Classical Guitar Society as such, with members etc. There is a Swansea Classical Guitar Circle that meets in Sketty Community Centre run by Sylvia Barker (suburb of Swansea) every Wednesday evening and organises concerts and they have a website (http://webspace.webring.com/people/os/swanseaguitar/
). There is also a Classical Guitar workshop every Tuesday evening in Gorseinon Institute (small town about 5 miles from Swansea) and that is free and has a website www.gorseinon-guitar.co.uk
and you can pick up the link for Sketty Classical Guitar Circle on that site as well.
Like a lot places which are within 40 Miles of a Capital city (in this case Cardiff) everything tends towards the capital and Swansea has some of those disadvantages. Limited Arts funding obviously does not help either. There is a lot of interest in the Classical Guitar locally in Swansea and open-mic sesssions in pubs do occasionally feature it. So I don't know whether this counts really as a valid entry because they are more of a 'drop-in and keep dropping-in' rather than memberships etc. people are very committed though.