Unlocking means making the phone available for use on other carriers. On CDMA carriers such as Verizon, Sprint, US Cellular, Alltel, it doesn't mean as much compared to GSM carriers like AT&T, T-Mobile. So for you, the benefits are probably none.
unlocked means if you have an at&t phone, and you leave at&t and decide to go t-mobile for example, you can insert a t-mobile sim card on your at&t phone.
