This site, from Moneyextra, has a database of over 60,000 properties as well as lots of information about moving house. You can also compare mortgages from over 120 lenders. The database is taken from estate agents - there does not seem to be any method of advertising your home for sale on this site.
Housenet is THE place to look for UK property for sale on the Internet. Use Housenet to search for houses for sale and estate agents in England, Ireland, Scotland and Wales. FREE listings for residential property for sale in the UK and Ireland. Search for houses by area, house type, price and number of bedrooms or view the selection of estate agents.