Use ammonia lock products to neutralize the ammonia. Make sure you are dosing enough to lock up all the ammonia in your water source (exe. Prime will lock up .8ppm/dose so if your tap water is at 1.5 you need to use two doses of Prime). Then trust your math skills because the test kits will still register the ammonia in the water even though it's been converted to a non-toxic form. Once your tank is cycled, the bacteria will remove the non-toxic form of ammonia just as it would the toxic form. Else, you can buy ammonia blocks from a LFS that will remove the locked-up ammonia. HOWEVER, these also might prevent your tank from cycling.
Another thing you can do is a 'silent cycle' (do a search of the forum to find info) which basically means adding a bunch of live plants to your tank. The live plants will help remove the ammonia too (if I remember right).
BTW: I read somewhere that if you have high levels of ammonia in your tap water (I do too) that it means your water source is treated with chloramine instead of chlorine.
