When i give adalon the eggs she transports me to somewhere. Where does she take me? and can i plunder the other dungeons while I still have her eggs without her getting mad?

You are transported to an area which is part of the Kuo-Tao (sp?)-dungeon. It is in the western part of the Underdark map (it is not marked).
In my games I delivered the eggs asap. But, after being transported you can go back to the rest of the Underdark (Beholder lair, Maind Flayers, Snerfverblin,etc.) I think re-entry to Ust Natha is denied, but never tried that one.