The new Gevey Ultra S is now available for pre-order and will unlock your iPhone 4S without the need for a jailbreak. Your order will come complete with one Gevey SIM tray and an Ultra S SIM which should be plug and play and require no emergency dialing for it to work.
It's worth noting that the Ultra S is only compatible with the GSM version of the iPhone 4S which means if you've got a Verizon or Sprint model, you'll have to sit this one out. Gevey also claims that the Ultra S will operate under a 3-volt standard which allows for less battery consumption. Basically, you shouldn't lose any battery life due to the unlock. It will also be completely untethered so no worries about rebooting and losing the unlock.
While the Ultra S will unlock 2G and 3G bands on all networks, in some cases you may still be restricted to 2G access. This is common with unlocked AT&T phones on T-Mobile who only have EDGE access. The Gevey Ultra S boasts the following feature set -
It's worth noting that this unlock doesn't require you to alter or cut your SIM card, which is a plus over other unlocking methods. You can hit the link below to pre-order a Gevey Ultra S for $54.99 via applenberry. Much cheaper than paying international roaming fees on your native carrier when traveling overseas. Any of you planning to pick one up?