Among those I met were David Busby of Edoceo.com . Through his company, David provides small and medium-sized businesses with IT solutions powered by open source technologies.
David told me that he had written an Amazon S3 access toolkit in PHP. I urged him to release it sometime soon, and promised him that I would blog about it. Apparently my arm-twisting was successful -- earlier today he announced that phps3tk was now available!
phps3tk provides an API and a command-line interface to Amazon S3. Once installed, you can use commands like "s3 ls" to list bucket contents, "s3 get" to retrieve data from an object, and "s3 put" to store data in an object.
There is also a programming interface wrapped around the S3Cache, S3Connection, and S3Response objects.
Nice work, David!