You need to move fast PPC Riches is coming off the market
Service PPCs "Service" engines let advertisers provide feeds of their service databases and when users search for a service offering links to advertisers for that particular service appear, giving prominence to advertisers who pay more, but letting users sort their results by price or other methods. Some Product PPCs have expanded into the service space while other service engines operate in specific verticals. Noteworthy PPC services include NexTag, SideStep, and TripAdvisor. Pay per call Similar to pay per click, pay per call is a business model for ad listings in search engines and directories that allows publishers to charge local advertisers on a per-call basis for each lead (call) they generate. The term "pay per call" is sometimes confused with "click to call"[1]. Click-to-call, along with call tracking, is a technology that enables the “pay-per-call” business model. Pay-per-call is not just restricted to local advertisers. Many of the pay-per-call search engines allows advertisers with a national presence to create ads with local telephone numbers. According to the Kelsey Group, the pay-per-phone-call market is expected to reach US$3.7 billion by 2010. http://www.squidoo.com/ppc_riches