I'm going to try to consolidate the various wikis here that address the steps needed to create a Mercury EBS Boot Instance.
As far as I can tell these are the ones:
Install Steps
1) Step by Step Mecury 1.1 Wiki
2) Set EC2 Consistent Snapshot
- http://groups.drupal.org/node/36766
- http://alestic.com/2009/09/ec2-consistent-snapshot
- http://www.shlomoswidler.com/2010/01/creating-consistent-snapshots-of-li...
Additional Information
3) Set up EBS for Mercury
- http://groups.drupal.org/node/33092
Not sure if this is needed since an EBS Boot Instance is already on EBS
4) Move Pressflow to the EBS Volume
- http://groups.drupal.org/node/73278#comment-230623