Redsn0w 0.9.13dev3 released to jailbreakiOS 6 beta3 by iPhone Dev team. Due to the fact that a number of packages] have not been updated so Redsn0w 0.9.13dev3 will not install [Cydia]. Only iPhone Dev team is providing you the tethered jailbreaks for iOS 6 beta so we appreciate the effort by MuscleNerd and his whole team. As iOS 6 b3is only for Apple’s enrolled developers so user stay away from this release and wait for the public release of iOS 6 which will be in September or October along with iPhone 5. Redsn0w is the famous jailbreak tool by iPhone Dev team for iPod touch, iPad , iPhone and Apple’s TV. Redsnow 0.9.13 dev 3 is the tether jailbreak that supports only A4 devices like iPhone 4, iPhone 3GS and iPod touch 4G. Apple is trying
to fix the bugs in iOS 6 so this is the third beta release by cuportino company in during month.
If you are using tether jailbreak then it means device is switched off or rebooted, you will need to reconnect to your PC or Mac. As stated above this jailbreak does not install Cydia, but you can use SSH or download .deb file to install Cydia

How To Jailbreak iOS 6 beta3 with Redsn0w 0.9.13dev 3

Step 1: Install iOS 6 beta 3
Step 2: Place your device into DFU mode
Step 3: Download RedSn0w 0.9.13dev3 and open it

Download for windows
http://www.iphoneleaks.net/2011/07/download-redsnow/

Download for mac
http://www.iphoneleaks.net/2011/07/download-redsnow/