DEFRA waste pages: https://www.gov.uk/government/policies/reducing-and-managing-waste
Provides some good resources, and is where you will find the National Waste Strategy and other policy documents.
DG Environment: http://ec.europa.eu/environment/waste/
The waste pages of the European Commission contain a lot of information in particular on producer responsibility and recycling.
Lets Recycle:www.letsrecycle.com; and Wastewatch: www.wastewatch.org.uk
Together these provide a lot of information about practical measures which have been taken to increase recovery and recycling.
Waste and Resources Action Programme: www.wrap.org.uk
This non-profit making organisation was set up to help deliver the targets in the Waste Strategy. It will play an increasingly important role in waste management over the long term.
Environmental Services Association: www.esauk.org
For an industry view, the ESA is the trade body for the Waste Industry and provides publications on many waste issues at http://www.esauk.org/esa_reports/
Valpak: www.valpak.co.uk
The largest compliance scheme concerning producer responsibility.