What you're looking for is the JSON-RPC API. You can either implement it directly (it's the OpenSocial JSON-RPC syntax), or use any of the available client libraries out there.
Our client library is written in Java and you can download it from http://code.google.com/p/orkut-os-client You will notice it really lacks documentation. But new documentation is coming soon! -- You received this message because you are subscribed to the Google Groups "orkut Developer Forum" group. To post to this group, send email to opensocial-orkut@googlegroups.com. To unsubscribe from this group, send email to opensocial-orkut+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/opensocial-orkut?hl=en.