evasi0n 1.1 has been released on the site with the latest fixes. You may have to clear your browser's cache to see it.
Note that you do not need to download evasi0n 1.1 if you've already jailbroken.
There is nothing in evasi0n 1.1 that is not already in Cydia.
You can find the links to download evasi0n here.
Evasi0n 1.1 (Windows): evasi0n-win-1.1-baad71faf69b65b5d97f8fc1391846d5778b289d-release.zip
Evasi0n 1.1 (Mac): evasi0n-mac-1.1-baad71faf69b65b5d97f8fc1391846d5778b289d-release.dmg
Evasi0n 1.1 (Linux): evasi0n-linux-1.1-baad71faf69b65b5d97f8fc1391846d5778b289d-release.tar.lzma
The update includes fixes which address issues with the Weather app and long rebooting times after jailbreaking. If you've already jailbroken you should not use evasi0n again; rather, follow these instructions to update your jailbreak.

For Windows
How to jailbreak iOS 6 using evasi0n [Windows tutorial]
For Mac
How to Jailbreak Your iPhone 5, 4S, 4, 3GS Using Evasi0n On Mac [6.X]
if you need a video guide, click here:
Watch the Video Tutorial to Jailbreak iOS 6.x Untethered [Video]