There are several ways you can search for a remortgage. You could ask friends or family members about their own choice of lenders (whether they are banks or building societies) and whether they're happy with their current deal.
You could always start your research by looking through some of the many specialist mortgage magazines that are now available. They can be a good source of unbiased information. They produce special features on particular products each issue, on the pros and cons different types of mortgage or remortgage for example. These magazines also tend to feature product comparison tables of the best deals available at the time of publication which is usually monthly. Many newspapers also feature specialist property sections which can be useful.
Researching potential remortgage products on the Internet can give you a great overview of what's available. You can check the websites of not only all the major high street lenders but also the websites of specialist remortgage and finance companies. Apart from the convenience of searching from home (and outside normal business hours), you are also able to compare the various interest rates for different products from hundreds of lenders.
If you're pressed for time or even if you find the sheer amount of information available daunting, you could approach an independent mortgage broker to do the searching for you. You'll need to give them details of your current mortgage situation and they'll hunt down the best deals based on your circumstances. Brokers will often have access to information about special deals which aren't available through a high street bank. Some mortgage brokers may charge you a fee for their services, so ask for this information before you go ahead with this option.