Met Office Cloud and Pressure Composite. Nice summary view.
Met Office METARs for East Anglia. Registration required, but free.
Aviation Weather. Top Site. Great for Met Office pressure forecast charts.
Other good pilot's sites
Self Briefing. Lots of stuff here, NOTAMs and the AIP - AD section is very informative. Horrible user interface (fix it!), but this info is pretty much nowhere else. Registration required, but free.
The Flyer website. See the forums for good discussions, experienced and student.
The CAA's Safety Sense Leaflets. Top Reading, not just safety really. Broad yet concise.
PPL in the US? Some experiences. A cost analysis.
Alasdair's Flying Links. A good links site. I modified an .xls logbook I found there.
Good education for all pilots via how it unfortunately all went wrong for someone else. Updated monthly.
I shall be speaking to these people about kit plane building in the future, I expect.