I guess it's more of a Palaeolithic theme but Ice Age is a fine family film that raises many a smile in our house. It's the closest I can get to raising any sort of interest in prehistory with my mob.
Can't say I was that impressed with Ice Age 2
(-:

3rd Stone had an article on the WWW covering megaliths in film but their website seems to have disappeared. I came across this site which may be of some help.
http://www.trussel.com/prehist/prebul.htm

cheers
fitz