If your tap water tastes good for drinking- it is most likely fine for mashing.
If you are first starting out- I would focus more on hitting mash temps, keeping everything sterile, and fermenting at a proper temperature for the yeast- then you can spend more time reading about water chemistry.
If you want to start reading up- this is a great nerdy book if you are into that type of thing- http://www.amazon.com/Water-Comprehensive-Brewers-Brewing-Elements/dp/0937381993
If you are worried about the chlorine you can boil it off, charcoal filtered out, or you can simply leave 5 gallons of water uncovered overnight and it is good to go. If you have chloramine you can use Campden tablets that contain potassium metabisulphite to remove it.
Good water is key to making good whiskey- but I have been using city tap water for a long time with good results. (I live in a town with really good tap water though- so that does help)
Hope that helps