To change the service to be used from Flickr (which is still the default) use the following code:
Flickr.CurrentService = Flickr.SupportedServices.TwentyThreeHQ;
Flickr.CurrentService = Flickr.SupportedServices.Zooomr;
This code is subject to change in the future. It is currently a global setting but I may change this.
Support from 23HQ and Zooomr for the Flickr API is not guarenteed. Both services do not support the full range of Flickr services, and may in the future support other methods not supported by Flickr.