According to this new post on Davey Shafik's blog, there's now a Universal Binary of the latest beta version of Zend Studio available.

I just wanted to make a quick note, to say that Zend Studio 5.5 Beta, though the installer is PPC, the actual ZDE application is an OS X Universal Binary. The speed difference is more than noticable!

You can find out more about Zend Studio from this page on the Zend website and sign up to become a beta tester to gain access to this just off the line Universal Binary release.