• BBC. Excellent site with a good weather section for UK
• Met office. UK met office with shipping forcasts
• Meteo. Link to spanish web site which buys the synoptic charts from the met office and gives them away for free here
• YBW.com. Home of yachting monthly amongst other mags. Good liveaboard forum.
• Weather online
• Ugrib. Really good bit of free software. Downloads just the area which you select so files are normally small (as long as you don't select the entire Atlantic).
• Wind Guru. Aimed at surfers but very useful. Downloadable google earth file shows locations.