Zen Cart contribution which would help you export easy your products into PriceRunner.com - one of the best Pay-Per-Click service.

The website PriceRunner is a price comparison service launched in Sweden in 1999, and since bought by ValueClick. It allows users to compare prices on a range of products.
PriceRunner uses a combination of screen scraping retailers websites and files supplied by the retailers themselves. These prices are matched against a backend database. This is done by using both a fuzzy logic automatching system, and manually by admin staff. PriceRunner.com was designed to provide consumers with easy online access to specifications and prices for a wide variety of products.
PriceRunner is similar to other price comparison services in that it is financed by advertisers, who pay on a pay per click model. It also uses web banners provided by sister company, vcmedia.

Main features:

easy to use and configure
multilanguage support
multicurrency support
ability to export only selected categories
ability to include/exclude products marked "out of stock"
ability to include/exclude products with zero quantity
capability to include/exclude products with zero price
capability to strip HTML from Product Names
capability to strip HTML from Product Descriptions
capability to set default shipping cost
ability to limit number of products exported
ability to set currency that is used during export
ability to customize name of the export file
inline text recommendations for fast initial configuration
ability to automatically upload feed via FTP
ability to send feed via email
third party sales channel tracking (Google Analytics, WebTrends, OneStat, 123LogAnalyzer, Netmining etc)
optional GZIP compression of feed contents
additional Live Product Feed URL options
ability to validate feeds (XML-based feeds only)
ability to store feed on your server
multiple export configurations
preconfigured Google Analytics......