Most of the apps on the apps store have a link to a support web site and a app web site. Is this a requirement? Can you submit the app for approval before these links are 100% done?
Depends on your definition of "done". A simple static page is plenty, so you might as well submit with that and update the page later (especially since reviewing takes time, you don't want to delay submission).
FWIW, I set those links to http://www.apple.com when I submitted my app. I didn't get my web site up until after the app was approved. I changed the link once the site was ready, after the app was approved, before the app was released.