iOS/iDevice nightlies are back up: http://mirrors.xbmc.org/nightlies/darwin/ios/
ATV2 nightlies are still on hold for the time being till some stuff gets cleared up.
As always, be sure to backup your userdata folder regularly when playing with nightlies. (I haven't tried it myself yet, but we also have a new Backup add-on that can be used to backup and restore settings, found under Programs in the XBMC.org repo.)
The wiki instructions have been updated again with nightly install install instructions for both iDevices and ATV2.
You can go back to stable XBMC v11 by using Cydia/NitoTV/command line instructions.
Same warnings as before applies: These are unstable builds, not for the faint of heart, expect there to be bugs. If you have issues and want to post about them/get help, then you MUST include debug logs, etc.
Team-XBMC Wiki Guy
Joined: Jan 2011
Location: Arizona, USA
2012-05-06 22:13 Post: #1
You can make easy links to the XBMC wiki using double brackets around words: [[debug log]] = debug log, [[Add-on:YouTube]] = Add-on:YouTube, [[Adding videos to the library]] = Adding videos to the library, [[userdata]] = userdata, etc