when accesss webservice asking for userid and pasword?

hi folks,

I created a web sevice to access active directory, it works fine on my developement PC, but when i try to run it from outside the network in the same company(different network). it asks me for userid and passowrd. after supplying userid and password i am able to achieve that the details.

but is there any way i can pass the credentials in webservice itself.

any ideas?
...