Aside from chlorine or chloramine that may be added by the municipal water authority, tap water should generally be safe. A good water conditioner will detoxify chlorine/chloramine, and most also deal with heavy metals which is fine. Beyond that, unless there is something in the water, no other products should be necessary.
I highly recommend API Tap Water Conditioner. It is the most concentrated one available (for just chlorine) and that means you use less, a benefit for the fish and your wallet. StressCoat was mentioned earlier, this is not a good product as it contains aloe vera and long-term this does seem to harm fish gills.
The main thing now is to get the cycling done, and Colin I think explained that. Daily water changes to keep ammonia and nitrite as low as possible. The tap water tests I suggested earlier will determine if either of these (and nitrate too) are in the water.
Feed sparingly, no more than once a day, missing alternate days won't hurt either. The less that goes in, the less comes out to raise the ammonia/nitrite.