You can now use Google checkout as well as PayPal to sell your digital content with PHP-eSeller.
You need a Google checkout account which will identify your merchant codes.
Enter these into the admin area of PHP-eSeller and then select the tick box that enables Google checkout in the shopping cart. The shopping cart will then display both the PayPal and Google Checkout buttons.
Google checkout also has a sandbox test area which is easy to use and work with.
In someways Google checkout gives a better customer experience than PayPal.