See how the London Olympics 2012 site is developing with this roving cam in Newham (northeast London)
http://apps.newham.gov.uk/Webcam/

A view of the arch on the new Wembley stadium. A good cam for observing the build-up of shower clouds in northwest London

http://www.wembleystadium.com/brilliantfuture/webcam/arch.htm

A BBC camera viewing Trafalgar Square, although it does seem to flip to Admiralty Arch occasionally!  It updates every 5 minutes.

http://www.bbc.co.uk/london/content/webcams/trafalgar_square_webcam.shtml

A camera on the roof of the BBC Television Centre looking across west London.

http://www.bbc.co.uk/london/content/webcams/tvc_webcam.shtml

The BBC version of the Wembley Stadium Arch in north London.

http://www.bbc.co.uk/london/content/webcams/wembley_webcam.shtml

The busy High Street in Winbledon; southwest London.

http://www.forbidden.co.uk/demos/live/

Oxford Street, the most famous road in the Capital. Situated in central London.

http://www.streamdays.com/camera/view/oxford-street-london