Here's what I know about so far:
- Bucket Explorer -A user interface for Amazon S3. Runs on Windows, Linux, and Mac systems, available in three editions (basic, commands, and team).
- CloudBerry Backup -A backup and restore program that uses Amazon S3. Runs on Windows. Includes scheduling and optional data encryption.
- CloudBerry Explorer -A file management tool for Amazon S3. Runs on Windows and includes a PowerShell interface.
- CloudBuddy -A set of management and analytical tools for Amazon S3. Runs on Windows, and there's an API and an associated SDK.
- Cloudgrapher- This site graphs CloudWatch data using CloudViz. It shows data from EC2 instances, Auto Scaling Groups, and Elastic Load Balancers.
- The Cloud Market -A catalog of Amazon EC2 images (AMIs); there were 8,279 images cataloged when I wrote this post.
- CloudViz - An open source toolkit for visualization of CloudWatch metrics. Read more about it in the recent blog post Introducing CloudViz.
- Decaf -An Android application that lets you manage your AWS resources from your mobile phone.
- enStratus -Management of AWS resources including Amazon EC2 instances, S3 storage, Elastic IP Addresses, CloudWatch, Elastic Block Storage, Auto Scaling, Simple Notification Service, and CloudFront. Automatic application deployment, encryption, key management, and more.
- iAWSManager -An iPhone application to manage AWS resources including EC2, S3, CloudFront, SQS, and SimpleDB.
- RightScale - System dashboard, system management, RightImages, and ServerTemplate library.
- S3 Backup - Fail-safe, encrypted online backup. I've been using this for my personal backups (200 GB and counting).
- S3 Browser -Windows client for management of S3 buckets and files.
- Scalarium - EC2 cluster management with auto configuration, auto healing, and auto scaling, along with one-click deployment. Watch the screencast to learn more.
- SOASTA -Load and performance testing from the cloud from a browser-based Ajax-style interface. Watch the load test demo.
- VPN-Cubed -Create an overlay network, with full control of addressing, topology, protocols, and encryption. Read the technical overview to learn more.
- Ylastic - Management, monitoring, and alerting for EC2, SNS, SQS, SimpleDB, CloudWatch, Elastic Load Balancing, Auto Scaling, and Amazon RDS. Supports scheduled tasks and multiple AWS accounts.
Here are screen shots and logos from all of the applications featured above (created by AWS-powered Animoto):