Sony Ericsson provides a free software called the Bluetooth Remote Control that enables you to use your Sony Ericsson based Bluetooth-enabled phone to remotely control your Windows or Mac computer’s keyboard and mouse functions. Sony Ericsson phones support the Human Interface Device (HID) profile which defines the protocols, procedures and features to be used by Bluetooth HID such as keyboards, pointing devices, gaming devices and remote monitoring devices. You will also need to use a Bluetooth stack which supports the Bluetooth HID profile.

Windows- http://developer.sonyericsson.com/getDocument.do?docId=71477
Mac- http://developer.sonyericsson.com/getDocument.do?docId=71480