I have been trying to get Pro Sites to work, but the activation emails are not being sent.
I looked through the previous tickets and a similar one said that anti-splog was causing a problem with the signup page. I deactivated anti-splog but it didn't help.
I then deactivated Pro Sites and i was able to create a site and the activation email was sent.
I then reactivated Pro Sites and changed some of the settings. When I unchecked 'Signup on Checkout - Disables WordPress Signup', I was able to create a site via 'wp-signup.php' but I was still not able to create a site through the Pro Sites checkout page.