Vooma's new Peel PG92 handset case isn't the first to bring dual-SIM capability to the iPhone 4, but it may be the most elegant. The accessory, which has yet to be released, essentially consists of an extra battery pack and an unlocked SIM slot. All you have to do is download Vooma's customized app to your jailbroken iPhone 4 or 4S, strap on the Peel PG92, and insert your spare SIM card into the case (judging from the photos, it appears that the device is tailored for mini-SIM cards, rather than micro-SIM). Once that's taken care of, you'll be able to place calls via the app and external SIM, using a dialer interface that's only slightly different from what Apple offers. No word yet on pricing or availability, but you can sign up for more information at Voom's website, linked below. Otherwise, check out the coverage from our friends at TechCrunch, who managed to get their hands on a pre-release model.