Kajeet is CDMA.At the same time,your phone supports GSM carriers only.So you can't use Kajeet service on your mobile phone.But if your are interested to use other GSM carrier than your current network carrier means,your phone is unlocked one.If it's locked by particular network,you will need to unlock your mobile phone.You can unlock your phone by network unlock code.If you need an unlock code visit Unlock-Zone.com and you can get free how to enter unlock code instructions MobileUnlockGuide.com I hope it will be very useful to you.