I read an article stating that you can in fact boil water for 5-10 minutes to get rid of chlorine in the water. But in addition to boiling the water you should agitate or aerate it prior to use to replace the oxygen driven off while boiling.
Of course, you can do this with any amount of water for any sized tanks, but it would probably be a bit of a hassle if you have a larger tank. If you have a smaller tank (5 gallons or less) and don't wanna buy water conditioner this is a good alternative (and faster than leaving it out for 24 hours)
Boiling water may not remove chloramine, but it will concentrate any non volatile minerals. Maybe some in high concentrations are not good for aquariums.
An easier and more reliable approach to preparing aquarium water is warm or cool it to the appropriate temperature, then add a good tap water conditioner. Some conditioners treat for chlorine, chloramine, toxic nitrogen compounds and heavy metals.
If you change part of the water every week or so, it will help avoid water quality issues.
According to the Alameda County water district here in California:
Boiling is not an effective way to remove chloramines from water. The only practical methods of removing chloramines from water are using a water conditioner which contains a dechloraminator or by using granular activated carbon.
For a long time municipal water supply systems used chlorine to sanitize the water. As distribution systems grew longer and longer, the chlorine tended to evaporate. To cope with this, water companies started adding chloramine along with the chlorine. Chloramine does not evaporate like chlorine, so most tap water conditioners neutralise both things.
Some also handle toxic nitrogen compounds and heavy metals. Toxic nitrogen compounds continue to build up, so partial water changes are still important.
if you adding a water conditioner in your aquarium's and also water was very cold, never ever add a little boiling water. Because water conditioner has a sodium thiosulphate and combination between this and boiling water perhaps create a very dangerous poison and as a result fish passed away immediately.