Rob Allen has two new things he's posted in relation to the new Zend Framework 1.8 release - an update to his Zend Framework Tutorial and something he came across about the Zend Framework's autoloader.
Zend_Loader's autoloader has been deprecated in the upcoming Zend Framework version 1.8 and so you now get [an "autoload is deprecated"] notice if you use it.
The fix is simple - just change your call from the static registerAutoload method on the Zend_Loader library to a getInstance call on the new Zend_Loader_Autoloader. You can find out more information about this new component here.