Distilling water is really only successful in an industrial setting and most aquarists would find it exceptionally difficult to make themselves.
Yeah pots and pans in the basement with a bunson burner and a bunch of silicon tubing didn't work too great btw I should also add that if buying distilled, you should be on the watch for stuff labeled "distilled" that has fluoride and other stuff i nit...I started seeing it on shelves this summer in the stores; no clue what people would use that stuff for. It says in small letters at the bottom of the label that is has those addatives put back into it.