The same team who released the somewhat sketchy iOS 7 jailbreak has released a jailbreak for iOS 8.1. Currently, it's Windows-only, in Chinese, and doesn't install Cydia by default.
This jailbreak came as a bit of a surprise and is very rough around the edges. Users have reported that using a passcode crashes the system, a number of problems with Cydia, and a wide number of tweaks don't work. Cydia has been updated, but requires a manual install over SSH.
If you're adventurous, you can grab the Windows jailbreak tool at the PanGu site below, but we suggest holding off until the kinks are ironed out.