Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Classic is still included with the install/recovery discs that ship with new PowerPC Macs. It's not included with retail boxes of OS X. Apple also are telling people to expect no Classic support at all for the upcoming Intel Macs.

(Only because you called it a "classic UI", I'll mention that Classic does _not_ put the old-style appearance on new software. It's only for running pre-OS X software.)
 
It is indeed, although I don't think it's included in the standard install. You'll need to run the Classic Installer included on one of the CDs (I think it's labelled 'Additional Software' but I don't have my disks to hand), but it's a very quick and easy process – you won't have any problems.
 
I called it Classic UI because on the system folder the file is called Classic UI and Classic Support on my computer. But yeah, I was hearing that the MacIntel platform wasn't going to support programs running on PowerPC G3 and G4 and MacOS 9 and earlier. What's up with that? :confused:
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.