Assuming your parents are on a Mac, then perhaps iWeb or Rapidweaver.
There's been some issues raised about the size of pages being generated by iWeb, but it is drag n' drop and fully integrated into iLife 06.
Rapidweaver has a downloadable Demo (which allows you to generated 3 pages) allowing your parents to have a play first - it can then be 'turned on' once you purchase and enter a registeration number.
Another option is that you make the pages in Dreamweaver and your parents get to edit them with Contribute. If you use templates they can even make new pages with whatever layout you've made for them.