The Pangu jailbreak, which has been under development by a team of Chinese developers/hackers, is available, and confirmed working by a large number of users. Now, the instruction and overview video.
The jailbreak itself, while in Chinese, is somewhat straightforward.
Once downloaded (can be found from its homepage here, and is currently available for Windows with a Mac OS X version coming soon), you just need to open the program, uncheck the box, click on the jailbreak button, change your device’s date to June 2, 2014 (when prompted), and run the Pangu app to finish things off. When complete, you should see Cydia on your home screen, ready to be used to install your favorite tweaks and other packages.