choreographies implementation && access point

I´m a bit confused in the way you can use a choreography once it has been described with the XML interfaz.
* Wich is the access point? Is it in the choreography WSCI, or in te particular WSDL from the different services?

* Once the choreography interface is describes, should we interpret it or compile it; or should we create an aplication that shows the behavier previously described.

Thanks in advance