Here are some useful links that can inform and help you make your stay an informative one:

London transport www.thetube.com
London Time Out www.timeout.com/london
United International College www.uiclondon.co.uk
London Tourist Board www.londontouristboard.co.uk
New Zealand Homestay and Farmstay www.nzhomestay.co.nz/
Australian Homestay and Farmstay www.australianhomestay.com