Hello Gordon:
adCenter API access is currently in a pilot phase, and is by invitation only. The pilot has certain requirements that all advertisers must meet prior to qualifying for API Access. One of those is, you
must have an existing Premium account with adCenter, and be in "managed service" with Microsoft Advertising prior to qualifying for that access.
Please reach out directly to your current Microsoft Advertising
representative for more information and details. If you do not have a Microsoft Advertising account representative then you can contact our standard support team for more details on that. You can find out more information at the following sites: http://adcenter.microsoft.com, or http://advertising.microsoft.com
Best,
Bill Bledsoe
Operations Program Manager - API
SMB Advertising
Microsoft Advertising