Can I use TIBCO General Interface with PHP? Or better, with CakePHP? If it's possible, how can I do that? Maybe some documentation in the web? (I search but I don't find anything). Thanks.
Yes, a PHP application can generate all of the data formats which GI uses, such as raw XML, JSON, or SOAP.
Have a look here: http://uk.php.net/soap to get started writing PHP-based web services