|It shouldn't be necessary for you to know the DNS.|
With my mobile (BlackBerry) i just open it's wireless setup utility, it finds my wireless router, and all I have to do then is enter my router's wireless key and press "Connect".
I know, however, that Nokia does things differently, and some of their handsets are just plain stupid and terrible to use. I suggest you get a different make. My wife just upgraded her old Nokia to a new model and she hates it already.