The issue of copyright is complicated by the fact that different countries have different laws with regard to copyright material.
Essentially the same laws apply to material on the Internet as to material published via any other medium.
Before using material on your website which may be copyrighted by someone else you should obtain their permission to use it. Examples of such material would be logos, photographs, written articles etc.
Permission may also be needed for links to material on other websites.
Material which you may publish on your website should also be protected by copyright - the use of the copyright symbol © on such pages is highly recommended.
For further information on copyright and intellectual property, please visit www.ipo.gov.uk
A search of the web will also find more information on this topic.