This is a good book, but hard to get going with. It is slightly out of date. I recommend starting with the online tutorials first and then jumping to Chapter 3 and reading from there.
Setting up Lucid Lynx (Ubuntu 10.04.1 LTS) on an EC2 Micro Instance? If you want to continue to SSH into that server don’t reboot it. That is unless you modify you ssh config to change when it actually starts up the SSH service.
Simply open /etc/init/ssh.conf with vi or nano and replace:
start on filesystem
start on (started network-interface or started network-manager or started networking)
While this is not ideal and is not a great long term solution, it will do the trick and let you spin up instances from your ami that you can actually connect to.
This has been fixed in 10.10 and I believe there is a patch released for 10.04 already as well. I will check on this and post the official ami id that will let you spin up a Micro Instance with the issue fixed.