I know it's not free - But I'm 99% sure Macromedia DreamWeaver has an in-built function to do that. You can also convert back the other way... if it only has to happen once, find someone with DreamWeaver and send them the files
Hmmm.. I downloaded the thirty day trial to see if it could do just this about 4 months ago and couldn't even find the functionality. If it could, it would almost be worth the highway robbery they call a license fee. Almost but not quite.