CPC-List.com
Listing of pay per click search engines. Offers reviews, special PPC promotions, and general reference on the PPC industry.

Pay Per Click Analyst
Reviews of pay per click search engines.

Pay Per Click Bid
Offers pay per click search engine review, pricing, management software, keyword bid management tools and advertising costs information.

Pay Per Click Guide
Reviews the best and worst pay per click search engines on the Web. Includes web promotion tips.

Pay Per Click Guru
Compare pay per click search engines and other useful PPC tools. Browse information on various pay per click search engines, resources and tools.

Pay Per Click Search Engines Reviewed
Aims to review all sites that charge money for listing or ranking a site.

PPC-Directory.com
Listing of hundreds of pay per click search engines, reviews of bid management tools, scripts, and sites.

Smarter Scripts
Offers scripts to help make websites more interactive. Offers Smart Search for building pay-per-click search engines, as well as other products for web promotion.

UK Pay Per Click Search Engines
Reviews a few engines and examines how their syndicated partners display results.