The simple way to determine if you have chlorine or chloramines in your drinking water is to call your municipal water supply, like Jan suggested. They'll be able to tell you how they treat the water.
Chlorine will eventually dissapate from the water. This is accelerated by using some sort of aerator (an air stone). Chloramines are a chlorine-ammonia molecule, and will not dissapate. These need to be removed by chemical means. The chemical breaks the chlorine-amine bond, so you're left with chlorine and ammonia. The chlorine will dissapate (just like straight chlorine treated water), and the ammonia will be converted in your biological cycle.
If you do have chloramines in your drinking water, treat with the simplest dechlorinator you can find. I've used many over the years, and they all seem to be equally effective. I usually use half to three-quarters of the recommended amount. I do not recommend those that 'lock' ammonia. These just convert the ammonia to another form. They do not remove the ammonia.