Next question, which I should have asked already, is whether you are an extract or All-grain brewer. If you are an extract brewer, the water does not matter.
If you are an all-grain brewer I recommend reading Designing Great Beers. It provides a detailed explanation of the different water profiles and gives some information on how to adjust your water. I'd also recommend talking to other brewers in your area as they can give you information on what adjustments they make.