Here are some links that you might find interesting:
Localised Sites-
Brno Architectural Manual
Thoroughly detailed site covering the modernist and functionalist buildings of the Czech city of Brno.
Ideal Homes
Site covering the growth and significance of suburban South-East London.
Regional Modernism
Covers the documenting of Modernist buildings in the New Orleans region.
Heroic: Boston Concrete 1957-1976
An exploration of the concrete buildings of the Boston Redevelopment Authority.
Manchester Modernist Society
Website grouping together Manchester's many Modern Buildings. Also publishers of The Modernist magazine.
Good Causes-
Save Finsbury Health Centre
Campaign to save Lubetkin's 1938 Modernist Health Centre
Alexander and Ainsworth Estate
Website of the residents association of this 1970's modernist Camden estate.
Arlington House Margate
Blog detailing the fight to save the 1964 Brutalist building.
Preston Bus Station
Website dedicated to saving Preston's 1969 masterpiece from demolition.
Northview
Site detailing the fight to preserve this 1930's Holloway development.
References-
20th Century Society
Originally the 1930's Society, tireless campaigners for recognition of 20th-C buildings.
modern architecture london
Excellent website exploring London's modern buildings.
Post War Buildings
Online resource detailing Britain's Post-War buildings.
Modernist Britain
Site featuring the many British Modernist buildings with wonderful illustrations.
Hanger Hill East Residents Association
Residents association website of the rich Art Deco area of Hanger Hill and Park Royal.
Modern Houses London
Architectural guide to modern houses throughout London and beyond.
Cinema Treasures
Great website featuring cinemas from all over the world and through the ages.
Urban Design
TFL website detailing Tube stations of architectural merit.
Blogs-
Ruins of Great Britain
Owen Hatherley's site detailing his varied urban trawls.
English Buildings
Philip Wilkinson's blog featuring the diverse wonders of buildings in England.
Islingtongue>Leystongue
John Rogers charts his perambulations around London.
Other-
Middlesex County Council
Nick Papadimitiriou's shrine to the Middlesex of the mind.
Middlesex County Press
Another Middlesex themed website, this time from Patrick Matthews.
Homespun Vintage
Site showcasing the best of 20th Century British art and industrial design.
Londonist
As it says on their website "London and everything that happens in it".
Greater London Industrial Archaeology Society
Society dedicated to recording and documenting Greater London's industrial heritage.
MIMOA
A user sourced online architectural guide.
Localised Sites-
Brno Architectural Manual
Thoroughly detailed site covering the modernist and functionalist buildings of the Czech city of Brno.
Ideal Homes
Site covering the growth and significance of suburban South-East London.
Regional Modernism
Covers the documenting of Modernist buildings in the New Orleans region.
Heroic: Boston Concrete 1957-1976
An exploration of the concrete buildings of the Boston Redevelopment Authority.
Manchester Modernist Society
Website grouping together Manchester's many Modern Buildings. Also publishers of The Modernist magazine.
Good Causes-
Save Finsbury Health Centre
Campaign to save Lubetkin's 1938 Modernist Health Centre
Alexander and Ainsworth Estate
Website of the residents association of this 1970's modernist Camden estate.
Arlington House Margate
Blog detailing the fight to save the 1964 Brutalist building.
Preston Bus Station
Website dedicated to saving Preston's 1969 masterpiece from demolition.
Northview
Site detailing the fight to preserve this 1930's Holloway development.
References-
20th Century Society
Originally the 1930's Society, tireless campaigners for recognition of 20th-C buildings.
modern architecture london
Excellent website exploring London's modern buildings.
Post War Buildings
Online resource detailing Britain's Post-War buildings.
Modernist Britain
Site featuring the many British Modernist buildings with wonderful illustrations.
Hanger Hill East Residents Association
Residents association website of the rich Art Deco area of Hanger Hill and Park Royal.
Modern Houses London
Architectural guide to modern houses throughout London and beyond.
Cinema Treasures
Great website featuring cinemas from all over the world and through the ages.
Urban Design
TFL website detailing Tube stations of architectural merit.
Blogs-
Ruins of Great Britain
Owen Hatherley's site detailing his varied urban trawls.
English Buildings
Philip Wilkinson's blog featuring the diverse wonders of buildings in England.
Islingtongue>Leystongue
John Rogers charts his perambulations around London.
Other-
Middlesex County Council
Nick Papadimitiriou's shrine to the Middlesex of the mind.
Middlesex County Press
Another Middlesex themed website, this time from Patrick Matthews.
Homespun Vintage
Site showcasing the best of 20th Century British art and industrial design.
Londonist
As it says on their website "London and everything that happens in it".
Greater London Industrial Archaeology Society
Society dedicated to recording and documenting Greater London's industrial heritage.
MIMOA
A user sourced online architectural guide.