Add a SalesFeed tracking code to your WordPress site. You need a SalesFeed account.
A very easy WordPress plugin wich adds a SalesFeed (http://salesfeed.nl/) tracking
code to your WordPress. The tracking code can be configured on the SalesFeed
settings page under your WordPress admin settings page.
Extract the zip file and just drop the contents in the wp-content/plugins/ directory of your
WordPress installation and then activate the Plugin from Plugins page.