Every major e-commerce shopping cart program  supports one or more e-commerce gateways.   For example, the following shopping carts are certified with the Network Merchants gateway:

Authorize.net gateway supports even more shopping carts.  For a list of shopping carts that are certified with Authorize.net, see the Authorize.net Certified Solution Directory. 

Many gateways such as Network Merchants support Authorize.net emulation.  If your shopping cart support Authorize.net, there's a good chance that it would support Network Merchants as well even if it's not on the list of certified Network Merchants shopping carts.