There’s now a full set of public Amazon EC2 AMIs for openSUSE 11.3. Refer to SUSE Studio: Public openSUSE 11.3 AMIs for the full list and further details.
You can also create custom Amazon EC2 AMIs based on openSUSE with Kiwi or SUSE Studio. Refer to SUSE Studio: New Amazon EC2 build format for details on how to do this in SUSE Studio. Studio only supports openSUSE instance-store (non-EBS) AMIs at this time of writing, but it will change soon. Also, you will soon be able to upload and create AMIs directly from within Studio (no need to download and run the script).