Apple relased iOS 4.3.3 for the GSM iPhone 4, iPhone 3Gs, iPod touch (3rd+4th gen), and the iPad (1+2) today. (Another update, iOS 4.2.8, is available for CDMA iPhone users.) This minor update changes the way iOS devices save location data.
The good news is that Apple hasn’t patched the untethered exploit used by the latest versions of the jailbreak tools redsn0w, PwnageTool and sn0wbreeze.
The untethered jailbreak is out! Redsn0w 0.9.6 rc15 is your answer.
More info here. For iPhone 4 on 4.2.8, redsn0w will result in a tethered
follow this tutorial to untether your redsn0w jailbreak: http://www.funkyspacemonkey.com/untethered-jailbreak-verizon-iphone-4-running-ios-428-redsn0w
(Yes. It's an untether pack on cydia.)
Source: 1, 2, 3