iOS 6.1.3 Jailbreak Released for All devices http://www.jailbreakandunlockios.com/
Today 19th April 2013 Evasi0n Just released their new version that can jailbreak ios 6.1.3 untethered!
This untethered jailbreak 6.1.3 finds a certain vunlerabilty in the settings kernel that apple didn't fix correctly.
How to jailbreak untethered 6.1.3 Guide:
-Download the evasi0n tool for ios 6.1.3 jailbreak untethered.
-Open the evasi0n jailbreak 6.1.3 tool
-First connect your iDevice to our pc/laptop windows or mac
-Make sure your iTunes is closed before proceding.
-Hit the jailbreak button and wait a few minutes.
-After iDevices is turned up you can check cydia is working and also restart your iDevice to check the 6.1.3 jailbreak is really untethered.