Unlocking W580i AT&T locked

Hey guys I need help to unlock a W580i locked to AT&T. I would like to use XS++.
Can any one please guide me to unlock it. I am a complete noob. So I need step by step Guide.

22:44:28| XS++ v3.1 (Darwin) Ready !
22:44:28| Executed on Microsoft Windows XP
22:47:09|
22:47:09| Attempting to open the interface...
22:47:09|
22:47:09| TURN OFF PHONE!
22:47:09| Hold 'C' button on phone and connect phone NOW.
22:47:09| You have 30 seconds...
22:47:09|
22:47:10| Baseband ID: 9900
22:47:10| Protocol Version: 3.1
22:47:10| Warning: IMEI name does not match GDFS name (IMEI:NULL GDFS:W580)
22:47:10| ...using GDFS name
22:47:10|
22:47:10| Profiling SEMC phone...
22:47:10| Platform: DB2020
22:47:10| OTP CID: 51
22:47:10| EROM CID: 52
22:47:10| EROM Color: Red
22:47:10| IMEI: 01157200xxxxxx
22:47:10| Phone ID: W580
22:47:10| Region: CINGULAR
22:47:10| CDA: CDA102774/102 R25A
22:47:10| Firmware Version: R8BE001
22:47:10| EROM: R3A022
22:47:10| Ready for operation!

Thanks a lot..!!! :)