A powerful e-commerce webcart shop system for small, medium and full-sized merchants as well as wholesalers.

http://xt-commerce.googlecode.com/files/xt-commerce-v3.04SP2.1.zip

older versions can be found here:

http://www.pc-service-backes.de/downloads.htm

german docs:

http://www.nandlstadt.com/xtcommerce/xt_commerce_anleitung_dokumentation.htm

http://www.mediafire.com/?9cgjmnndebt

http://www.xt-commerce.com/ (in germann language, english version available)