Wind Guru: Largs - Very good for hour by hour forcast of wind and wave direction & strength

BBC's Marine Weather Site- Very Comprehensive
Met Office- Doesn't really need an explanation!
Net-Weather- Good for 7 day and even month long outlooks
UK Wind Map - Excellent for current wind conditions
UK Sail.com - List of loads of other sailing weather links
Severe Weather UK - If you fancy doing some storm chasing
Accu Weather - Good sailing weather page including tides and sat images
Weather Online's Sailing - Good for long range wind & synoptic chart forecasts
Yacht & Boating World's Weather Site - Pretty good and easy to use