We are launching a new web portal in a couple of months. However over the next couple of months we will have placeholder design which tells a little about the portal, and allows users to enter in their name and email address, for a chance to win 1 of 1000 invitations to the private beta version.
Once the user inputs his Name and Email and clicks 'Submit', He gets an option(AJAX probably) asking if he is interested to 'Invite his friends' too. Then he has the option to import all his addresses from 'Yahoo', 'MSN', 'Gtalk' and 'AOL' and all those email-ids imported will be sent the 'Invite mail' ([url removed, login to view] after the user's consent) and an option to enter individual email-ids.
We require this to be completed in the next 4 hours.