problem with web services

Hi all

we are creating a new web service,sql and database are in one server with windows server 2008 "Pc1". web services and navision 2009 client are in other server with windows server 2008 "Pc2". the service works correctly (we watch the service in the explorer, and the publicated codeunits too) when we are working in Pc2, i think that this works fine because we are working in local, but the problem begins when we try to consume the web service from another pc. when we try watch the service in the explorer wants to loggin with an user. i think that is a problem with the delgation of the users. my question is how can i configure the users that have to consume the web service?.what is the set up Delegation??

thank you so much, and sorry for my english..