To unlock your samsung galaxy SII you need an unlocking code. if you unlock your skyrocket it will work on any GSM phone network carriers. The unlock code Will remove the SIM lock on your Samsung Galaxy S II.
You can get your unlockcode from a trusted online vendor like http://unlockgenie.com/
You should now be able to use your unlock code and the steps below to fully unlock your Samsung Galaxy S II to other carriers.
How To Unlock Samsung Galaxy S II Skyrocket
1. Power on your Samsung mobile phone with an unaccepted SIM card inserted.
2. Your Samsung mobile will prompt you for a password (unlock code).
3. Enter your Samsung unlock code.
Otherwise, if your Samsung mobile phone displays “Insert Correct SIM Card” then:
1. Turn on your Samsung phone with an UNACCEPTED SIM card inserted.
2. Type: #7465625*638*CODE# (Where CODE is your Samsung unlock code.
follow this link to get your unlock code :- http://unlockgenie.com/