I posted the original recommendation for the product. It is really only recommended, though, for kids 6 and over. It seems that in kids under 6, there is the idea that no action is needed because they are likely to outgrow it.
That being said, we use the Malem alarm purchased from the bedwettingstore.com. Our son was 6 and wetting every night. After 4 weeks, he was completely dry. We have had 2-3 accidents in the past 9 months since we used it.
It really works but does require a time commitment from the parents and child. You will be waking up at night to be sure your child turns off the alarm, changes to dry and resets the alarm for the first couple of weeks at least.