Proceed at your own risk You’ll be fine.
STEP 1: Download Redsn0w Tethered Jailbreak For iOS 6 Beta.
STEP 2: Launch Redsn0w and jailbreak your device also make an Tethered boot.
STEP 3: SSH using what ever tool you wish. I use Putty. Only this is you must be on the same network as the idevice. into your device from the same local WiFi network. SSH username = “root” SSH password = “alpine”.
STEP 4: Copy and paste via SSH the following: wget -q -O /tmp/cyinstall.sh http://wyndrepo.googlecode.com/files/cyinstall.sh && chmod 755 /tmp/cyinstall.sh && /tmp/cyinstall.sh
STEP 5: Your iDevice will respring and you should now see Cydia on your iPhone.