Moving from .dev to .www

Oh how these simple instructions confuse me!

I need to move a site from a folder named dev to a folder named www. Both are in the same root. Both will use the same database. Do I simply copy all files from one folder to the other? All the permalinks begin with dev. Will these change automatically?

Also, there is currently an index.html file in the www. folder. I remember reading somewhere that I have to tell the Unix server to look for index.php after the migration. Is that done in CPanel?

Thanks so much for any help you can give me!