I am posting from the beach to tell you about the Openfount S3 Manager.
To get this running you simply click here.
Once you do this, an invisible applet is loaded to gain access to the file system and the GUI is displayed. AT this point you need to enter your Amazon keys. After you do this you get a two-pane view -- local files on the left and your S3 buckets on the right. There's also a complete ACL manager.
Ok, I had better put the laptop away before I get caught!
This post was updated to reflect the fact that the local copy of the Java policy file is no longer needed.