This is a remake of the list done by Jeremy Zawodny (and brought to my attention by Martin), but i'll try to keep an up to date list. You should check the original list as there are alot of useful comments and ideeas over there and also check the list at amazon.

So, free tools:

So we've got and AWS account and we've got acces to EC2 and S3. Now everything is fine and nice, and i want to backup some of the data on my EC2 instance (let's say /etc and /var/lib/mysql ) and some data from another server ( the company's emails beeing that data) .
We've got the right tools, so let's backup the data, we never know when we'll be happy that even if the data center was hit by a meteorite we've got all the data backed up and tommorow we'll have everything back and running. But , wait, i see e problem, and the problem is the S3 acces method (the credentials). I have only one account that i'm using for uploading my ec2 images (this beeing done by an automated script that takes a snapshot of the system from time to time), for uploading the /etc dir from my etc instance and /var/lib/mysql from the same instance , and for backing up the emails from the company mail server (which is outside amazon). If we would have more machines, we would have more stuff to backup from different places , so more machines would have the s3 credentials.

Still looking, searching, reading for some way to have good, decent and often backups of the machine because if the power goes down or something happens, when the instance goes down .. you lose the data inside the instance.

Saw that there are threads about this on amazon's aws ec2 forum. Amazon's staff say that they are thinking about this and how they could provide either a database service (mysql or something else) or some kind of really useful and permanent storage (like the 160GB /mnt partition, but that doesn't wipe when your instance goes down).

The service that is already available and everybody is expecting to provide persistent storage is Amazon's S3 ( Simple Storage Service ). It's kind of a huge and cheap storage service, a walkthrough is available here. The problem for the time being is that there are no stable linux implementations.