Hobby and enthusiast sites:
Simon Cornwell - http://www.simoncornwell.com/lighting
English Street Lighting - http://www.streetlightonline.co.uk
Midlands Street Lighting - Claire Pendrous - midlandcountiesstreetlighting.50webs.com/
Tim's Streetlighting Page - hometown.aol.co.uk/streetlightinggb/
Eastbourne's Street Lighting - http://www.cooksonr.freeserve.co.uk
West Wales Street Lighting - http://wwsl.50webs.org (inactive at present)
Collection Streetlighting - http://www.leedsstreetlight.co.uk
Adam's Streetlighting - http://clerkbyron.com/lights
Colin's Street Lighting Collection - http://www.freewebs.com/thecolingrimescollection
Johnny's Streetlighting - http://www.freewebs.com/jonnysstreetlightingonline
Chris Nelson - http://mazeteam.co.uk/lighting/
DP - http://www.freewebs.com/sodiummercuryhalide
Local Authority, Professional and manufacturers;
Northamptonshire County Council - Street Doctor; to report faulty street lamps and damage to columns - http://www.northamptonshire.gov.uk/Transport/Roads_pathways/lights.htm
ABB Streetlighting - http://www.abb.com
Institute of Lighting Engineers - http://www.ile.org.uk
My favourite lantern, WRTL/Industria - http://www.wrtl.co.uk
Corus - http://www.corus.com