This is a online directory which consists of advertising links.This is the ultimate guide to London's advertising industry on the web.They have over 900 links in over 50 categories of interest.Check their site click here

They have an XML feed with which you can be having daily updates regarding advertisments.Even there is a search bar with which you can search the sites which you are searching for.The link for this one is click here

Even you can search for popular links,random links etc.You can even suggest a link for advertising.For suggesting a link click here