R-SIM 4 was released just a few hours ago to  perform iPhone 4 unlock on 4.11.08 & 4.12.01 basebands. They said earlier that it will take one more time than expected and claimed that they will release this hardware unlock within a week (proof). R-SIM 4  Unlock iPhone on 4.11.08 4.12.01 As you know the SAM unlock was released yesterday and what happens now? We see Gevey Ultra available to unlock iPhone 4 4.11.08 baseband and today their competitor releases R-SIM 4 to unlock 4.11.08 and 4.12.01 basebands on iPhone 4. Sounds kinda fishy, don't you find? R-SIM planned to release this unlock which frees your iPhone from 'expensive iPod Touch' curse for a long time. Probably they experienced some difficulties with developing of this unlock because it took much more time than for previous versions of R-SIM (R-SIM I, R-SIM II, R-SIM III). However they they probably thew all of their forces to solving this problem otherwise they could loose many-many potential clients that will choose free SAM unlock solution.

That's what official R-SIM site says about R-SIM 4 unlock on iPhone 4 4.11.08 & 4.12.01 basebands:

You can now unlock your GSM iPhone 4 with the new R-SIM IV. will work for iOS version 4.1, 4.2, 4.2.1, 4.3, 4.3.1, 4.3.2, 4.3.3, 4.3.4, 4.3.5, 5.0, 5.0.1 and 5.1 with modem firmware 1.59, 2.10, 3.10.1, 4.10.1, 4.11.08, 4.12.01. Be sure to check your firmware version before purchase!
The new R-SIM IV unlocks your GSM iPhone 4 running iOS 5.1 and earlier and now supports modem firmware versions 1.59, 2.10, 3.10.1, 4.10.1, 4.11.08, and 4.12.01. Currently, a tethered Jailbreak is available for iOS 5.1 for iPhone 4, and you will also need to install the latest Furious Mod file for proper operation.
R-SIM-4-4.11.08-4.12.01-baseband As you can see there's no big difference between R-SIM 4 and Gevey Ultra 5.1 tools, you still have to jailbreak your device and install Furious Mod from Cydia in order to get your device working in normal mode. Update: Use this link to find out how to use R-Sim 4 to unlock iPhone 4. The only significant difference is the price: R-SIM 4 can be obtained for $19.99 from official site when for the new Gevey Ultra solution you'll have to pay whole $49.99. Those hardware solutions are now under a big question mark as now wee have a nice and free SAM unlock that can unlock any baseband on any iPhone.