A useful site that shows the Declared Interests of elected councillors and MPs can be found here.
Members of Parliament and their interests
Local Councillors and their interests
I should declare at the same time that this is a site my own business Compelling Media is involved with.
The aim of the site is to provide free company and directors information, give my interest in Finance, ICT and Politics this is a great site to be involved with as it covers just about ever area I have knowledge in, all in one place.