IBillIt for AIM and ARB is a single library for integrating with Authorize.net's AIM and ARB APIs w/bonus features like line order item tracking, totaling, and custom data support. Authorize.net certified.
CIM Library integrates Authorize.Net's CIM Service. CIM enables PCI-DSS compliance. CIM Library uses a familiar object model and provides events and multi-threading options. Built on .NET. IT DevWorks is an Authorize.Net Certified Developer.