This is a double post. But the questions has already been answered. The alpha and i presume betas will have a self contained environment that automagically try to connect to the internet and download the latest and greatest installer code to make sure that the installation goes as smooth as possible. In some hardware configurations this will make the system show a solid gray screen for a few seconds. In others, where the system is unable to automagically configure the network interface, it will take even longer for the installer to show up... but it will ... eventually.
Maybe this should have been posted as a warning in the release announcement.