HowTo

NOTE: Make sure you have the latest API tools

wget http://s3.amazonaws.com/ec2-downloads/ec2-api-tools.zip

Create an instance from a snaphot

$ ec2reg -s snap-xxxxxxx -a i386 -kernel aki-xxxxx -d description -n name 
IMAGE ami-xxxxxxx

i386 is for a 32bit image, the kernel id is from the instance you got the snapshot from.  If you have a ramdisk then add that parameter too.

Install s2cmd on ubuntu

# apt-get install s3cmd
# s3cmd --configure

Leave the Encryption password blank and accept the default settings. 
NOTE: the configuration is saved in the user home directory so it must be run for each user that wants to run s3cmd