European Union law
This is the entrance to the main EU site, which has a huge amount of material on all aspects of the EU. Recent updates have made it easier to navigate and to search for and locate relevant information.
European Court of Justice
Lots of information about the workings of the court, access to the caselaw in English and French, and a digest and Index of the caselaw (in French).
Direct, searchable access to the Official Journal of the European Union.
Department for Exiting the European Union
Otherwise known as the “Ministry for Brexit”, this recently built website is largely press releases at the moment, but is starting to host some interesting publications emanating from the department as well.
The Scottish Government website also has a section dedicated to the implications of the EU referendum - http://www.gov.scot/Topics/International/Europe/eu-referendum
For serious legal analysis of all things Brexit, Article 50 and all, you could do no better than David Allen Green’s excellent Jack of Kent blog (http://jackofkent.com/).