Aviation Briefing
http://www.avbrief.com
Excellent weather briefing site- very comprehensive. All the information you need.

Aviation Weather for Europe
http://www.phd.nl/aviation/wx/
Airfield information, Winds Aloft, SIGMETS, TAFs & METARs.

MetOffice Aviation Services
http://www.metoffice.gov.uk/aviation/index.html
METAR s and TAFs, synoptic charts etc.

NOTAMs
http://www.ais.org.uk
NOTAM bulletins, supplied by National Air Traffic Services.

Daily Navigation Warnings
http://62.232.68.182/nav/nav.htm
Navigation warnings for the various FIRs, including royal flights.