Install is not yet implemented, I don't see anything on my web server logs when I install my app. Uninstall is working .
Here's what you get back from uninstall:
[oauth_consumer_key] => http://www.myspace.com/341711442
[oauth_nonce] => <secret>
[oauth_signature] => <secret>
[oauth_signature_method] => HMAC-SHA1
[oauth_timestamp] => 1204852123
[oauth_version] => 1.0
[opensocial_owner_id] => 7439663
[opensocial_viewer_id] => 7439663
You can see the variables by having php dump its output into a file:
$ob_file = fopen('callbacks.txt','a');
//Anything we output now will go to test.txt
echo "file written to...";
All of those variables you see in the file can be accessed with $_REQUEST['varName']...
Once install works, I would use it to setup initial user information, and add to statistics by storing into a database.