If you would like to find some general information, including introductions to the subjects, covering
Patents
Trade marks
Designs
Copyright
the links listed below will take you to some useful websites.

www.ipo.gov.uk/
This is the website of the UK Intellectual Property Office, and it covers a wide range of subject matter, from the basics to extremely detailed information on recent High Court decisions.

The Patent Office also announces important changes and new developments here.
http://oami.europa.eu
This is the official website for the European Community Trade Mark Office (Office for Harmonisation Internal Market Trade Marks and Designs).  It gives detailed information, and offers a variety of language choices (including English).

www.wipo.org/
This website belongs to the World Intellectual Property Organisation, which administers international treaties concerning intellectual property.  It provides a wealth of information from an international perspective.