iOS 8

You can indeed upgrade a jailbroken iPhone, iPad or iPod Touch (as long as they are compatible) to iOS 8. However, you will lose your jailbreak and all jailbreak apps and tweaks.

There is currently no jailbreak for iOS 8, and once you upgrade to the new iOS, you won't be able to return to an earlier version. So if you like your jailbreak tweaks, don't upgrade to iOS 8. At least not until a jailbreak is available for it, which isn't guaranteed.

iOS 8 is free for anyone with a supported iPod touch, iPhone or iPad. You can install iOS 8 for free by navigating to Settings > General > Software Update on your device, or by connecting your device to a computer and updating it through iTunes. You will need to be connected to a WiFi signal when installing iOS 8 to your device over the air.

UPDATE: Click here for instructions on how to jailbreak iOS 8.3 with version 2 of the TaiG Jailbreak Tool.

UPDATE: An iOS 8.0 - iOS 8.1 jailbreak has been released for developers by Team Pangu. The jailbreak does not come bundled with Cydia and is only compatible with Windows. Casual users should wait until a full version is released before jailbreaking their devices.

Continuity between iOS and OS X devices was a major concept during the iOS 8 presentation at this year's WWDC. It basically refers to the connectivity between one's devices and the capability of passing off tasks between them. Apple placed a lot of emphasis on this in the development of iOS 8 and OS X Yosemite. While not a whole lot is known at this point, we do know some features from Apple's iOS 8 preview.