Weather Forecasts

Met Office Inshore Waters Forecast
Met Office Shipping Forecast
Met Office High Seas Forecast
Met Office Navtex Extended Outlook
Weatherweb
BBC Coast and Sea (lots of information and very good)
Meteo France
Vendee Weather
Meteo Consult
Passage Weather
US National Weather Service NOAA site (incredibly comprehensive worldwide)
MetVU– a Kiwi site which does worldwide forecast charts
ECMWF forecast (surface pressure, geostrophic wind)
Theyr.tv – great site from Iceland(sadly now chargeable)
Accuweather
Weatheronline 
Metcheck 
WindGuru
XC Weather – UK
XC Weather – France
Westwind (more choices in presentation)
Magic Seaweed (very good for animated wind and swell)
Irish Waters
Mediterranean Waters around Italy (Italian Site, very good)

Current data

Met Office Marine Observations
Marina Chichester Bar
Warsash Sailing Club weather station (very good) – gives current Hamble conditions
Cowes Weather (wonderful)
Brambles Bank
Calshot Light Buoy
Southampton Dock Head
Isle of Wight weather
Lymington Starting Platform 
Hurst Castle 
Poole Harbour (wonderful site) 
Portland Harbour 
XC Weather – Wind reports for southern UK and France
British Isles Weather Buoys 
Burnham Yacht Harbour

Met Office synoptic charts

Current to 72 hours

Met office coastal observations (like the Shipping Forecast) updated hourly