Bernie ][ The Rescue is an Apple IIGS emulator (and I believe also emulates the Apple IIe as well, though I've never tested that). Aside from Sweet16 (for Mac OS X), this is easily the best Apple IIGS emulator for Classic Mac OS.
This collection features Bernie 3.0, along with every single version of Bernie ever released, and for those running Mac OS 7.6.1 or below, Appearance Manager is also included. Lots and lots of documentation and support for those who have trouble getting Bernie going is also included (Reading the support documentation requires a browser, I recommend Classilla).
PPC only as far as know.
Versions 2.6 and above should work on PPC Mac OS 8 all the way up to Mac OS 9.2.2
Versions 2.5.x and below should run on PPC Mac OS 7.6.1 and possibly below, however, the Appearance Manager is required, which is included.
Requires 256 colors.