At this time I'm not aware of if an IIS type webservice will be built in to Windows 10 IoT Core, but I do know you can develop your own simple web service if you like. This sample shows you how: http://ms-iot.github.io/content/win10/s ... Server.htm
And there is already another web service running on the device that you can use to help manage it. To access that just go to: http://<ip address>
And you should see the WebB interface.
I hope that helps.
Jonathan Tanner | Microsoft | Windows 10 IoT Core Insider Preview Support | This posting is provided 'as is' with no warranties and confers no rights.
I don't believe IIS would be supported on the IoT core platform, IIS binds to http.sys on the operating system and Microsoft have stated they are moving to a more portable way of hosting webservices; have a look at ASP.vNext and the DNX a number of selfhosting examples exists show the code running on Windows/Linux and Mac they shouldn't be any reason why these can't run on IoT (with a little effort)