First of all find the GND.. (Just use a multimeter)
Then power on phone (Dont care if the phone is dead due to software...press power on)
Check the votage btn GND and each pins Tx= 1.8v or 2.8v and Rx=1.7v or 2.7v
may be vary a little according to processers..
http://rapidshare.com/files/101438110/tx_rx.zip.html