Does anybody know of a webpage or phone number when one can check the provider behind a given (landline) phone number?

I am using sipcall and it offers free phone calls to any number within the sipcall/freecall network. Is there any way I can find out if a number is behind that network?

Thanks,
cla

Maybe you could ask Sipcall if the number is one of theirs?

Thanks Sbrinz! However, they have no contact number :-(