Here’s what people are doing with the Backpack API so far.

The Backpack API is implemented as vanilla XML over HTTP. Send the Content-Type: application/xml header to identify XML requests.

A page about using the Backpack API from Perl.

Net::Backpack is now available. Currently it only covers the pages section of the API, but other calls will be included before too long.

And here’s a link to Net::Backpack on CPAN.