iPhone Dev-Team has just released Redsn0w 0.9.7 beta 4 with a major change as the reds0w no longer requires you to install and run a separate program for the usbmux which caused a lot of confusion with the jailbreak process.
Starting with this version, redsn0w no longer requires you to install and run a separate program for the usbmux (this was a non-trivial procedure for many). It’s okay to keep that program running if you normally use it for ssh anyway. We also think we’ve fixed a race condition in the GUI that was causing redsn0w to crash during the “Preparing JB Monte Files” step. Nothing at all has changed on the iPhone side (where the main issues are still just Bluetooth and Skype).As the Dev-Team mentioned in the above quotation, so far, this version is still causing problems with Bluetooth and Skype. Now you have to follow our full step by step guide (Skip step 4 in this video guide) to untethered jailbreak your iPhone 4, iPod touch 4G and iPad.
Download Redsn0w 0.9.7b4 for Mac
Download iOS 4.2.1 for iPhone 4, 3GS, 3G, iPad, iPod touch
Download iTunes 10.1.1 for Mac