The MS IntelliMouse Explorer comes bundled with the excellent USB Overdrive utility for OS 9, which allows use of the scroll wheel and lets you map different mouse buttons to different commands in various applications. For my uses, it's the best mouse setup I've ever had.
But, under OS X, all of that functionality is missing, removing many (most?) of the advantages of this mouse. Does anyone know whether a.) USB Overdrive is slated to come to OS X, b.) any similar OS X utility exists, or c.) whether Apple was planning on building some/all of that functionality into OS X?