UPDATE : A Newer Jailbreak tool is now available, Check it out here.
The day you have been waiting for is here. The iOS 8 Jailbreak has been released by Pangu, a Chinese development team; Yes the same team that made the iOS 7.1 Jailbreak sometime back. As with most of their jailbreaks, you simply need to plug in and run their super simple program to jailbreak the iPhone, iPad, or iPod. With that in mind though, there are a few things you should definitely know/do before you click that big blue jailbreak button (backing up being a biggie).
Before we begin,
1) This works on the Following Devices running iOS 8.0-8.1.
iPhone 6 Plus
iPad (2, 3, 4, Air, Air 2, mini 1, mini 2, mini 3)
iPod touch 5
2) This will work with Windows or Mac OS X.
3) You must have the latest version of iTunes installed. If not, head here, download, and install the version there.
4) If you have a Passcode Enabled, please Remove it before you proceed. (Go into the Settings app on your device and temporarily disable it in the General —> Passcode Lock section. (You can re-enable it after the jailbreak is complete)
5) Turn off the “find my iPhone” Feature under iCloud Settings. (You can re-enable it after the jailbreak is complete)
6) Turn on Airplane mode to prevent any updates or data-driven apps from interfering with the jailbreak process.
7) Plug your iPhone in to the computer, and perform a Backup with iTunes.