British Beekeepers’ Association: http://www.bbka.org.uk/
Kent Bee-keepers’ Association: http://www.kentbee.com/
BeeBase, the National Bee Unit: https://secure.fera.defra.gov.uk/beebase/index.cfm
The ‘Hive Talking’ site supported by Plan Bee: http://www.urbanbees.co.uk/maps/
and our own group on Facebook at https://www.facebook.com/groups/359167444256663
For anyone interested in other social insects and solitary bees, there’s the BWARS site in the UK, and the BBCT site for anyone looking to learn about bumbles. For a general international review, the IBRA site is very good.