The new exploit will allow for users of devices like the the 4th gen iPod touch and the original iPad (both iOS 7-incompatible) to break free from Apple's walled garden, granted they're running iOS versions 6.1.3 through 6.1.5. The hack works by using the well-known redsn0w/sn0wbreeze tools, though do keep in mind that these two are tethered jailbreaks as of this writing. Luckily, however, there's a way to get the jailbreak to stick (untethered) by installing the so-called 'p0sixspwn' package available from the Cydia store once you achieve a tethered jailbreak. Also, do keep in mind that the iPhone 4 is currently facing some issues, and the jailbreak process is actually considerably more complicated, though many have reported success nevertheless, so check with the source at the bottom.
Best of all, the team is apparently very close to releasing a jailbreak compatible with Apple's A5 chips for iOS 6.1.3/6.1.4. The current ETA will see that one out by Christmas day – a fitting gift for the many iOS users who have been waiting anxiously.