Good PHP+S3 architecture?

[electrocatalyst]

Hi,

I'm building a website which will store multimedia files. They will be kept on Amazon S3. Only registered users should have access to files. Some users will be able to upload.

I would appreciate if someone could suggest a good architecture and general algorithms for the website. Should I let the user upload files to my website's diskspace first, then process the files, then upload to S3 or upload directly to S3? When user downloads a file, should I download it first to my diskspace or give them the direct link to the file?

Thanks in advance for advice!