How to I integrate (automate) my shopping cart with TrepStar.com cdDVDfulfillment ?

Learn about integration by Clicking Here

1) creating a free account and project. 
2) when at the project list area, click the integration button.  This shows you good information about integration.  Finally, for an example written in ASP, look here: http://www.trepstar.com/url-integration-example-asp.txt