Installing a WIC-1DSU-T1 creates a serial interface on your router, commonly Serial0/0 but the numbering will depend on your particular installation and router model. The physical layer T1 configuration is done via a series of 'service-module t1' commands under that Serial interface. Encapsulation and IP configuration is accomplished as you normally would. The below URL has an example as well as links to more information:
http://www.cisco.com/warp/public/107/wic-1dsu-t1.shtml
