www.acas.org.uk
The Advisory, Conciliation and Arbitration Service is an independent government funded organization whose aim is to improve employment relations. They provide information and advice on a range of employment issues including grievance and discipline. They have also produced a codes of practice and guidebook on handling discipline and grievance matters at work.

http://cipd.co.uk
The professional body for those involved in the management and development of people.  Considers good practice endorsing the Acas code and outlines the statutory procedures and the possibility of their reform. It also has reports and reviews of recent discipline and grievance cases.

www.direct.gov.uk/en/Employment/index.htm
This government run website provides advice and guidance on employment matters including employee rights and protection under the law. It has sections on discipline and grievance.

www.berr.gov.uk/
The Government department for Business Enterprise and Regulatory reform works with employers, trade unions and employees to improve the quality of working life for individuals, and create the conditions for business success. It provides advice and guidance on a range of employment issues including discipline and grievance.

www.tuc.org.uk  and www.worksmart.org.uk/
The Trade Union congress provides advice and guidance to its members on employment matters as well as liaising with government and employers in order to improve employee relations. The worksmart website is focused on providing news, advice and guidance to employees and union members.

www.hse.gov.uk
The Health and Safety directorate website is a useful source of information with regard to health and safety matters including legislation and may be of use if grievances and disciplinary cases are linked to this subject area.

http://europa.eu/pol/socio/index_en.htm
The European Union has its own website if you wish to look beyond the UK for disciplinary and grievance matters.