The Lafayette Building, 22-25 Westmoreland St, Temple Bar, Dublin 2
First of all, please note that the museum has just been relocated, so from now on it can be found in Temple Bar. The entry is free for kids under 5, which is reasonable considering the fact that many young kids are afraid of wax figures finding them too scary. Personally I would not recommend the Chamber of Horrors to children at all, but some parts like the Wax World, the Enchanted Forest and the Wax Hands (where you can have a copy of your own hand molded in wax) can be interesting for younger visitors as well.