Communities and Local Government
Access to approved documents.
http://www.communities.gov.uk/planningandbuilding/buildingregulations

Directgov
Information on the Building Regulations, including what they cover, why you should comply, what building work should comply and building work that is exempt.
http://www.direct.gov.uk/en/HomeAndCommunity/Planning/BuildingRegulations

Building Regulations Part L
http://www.building-regs.org.uk/part_l.html