Which rom are you using?
All CD32's use the same ROM, 3.1 (v40.62) I believe.
I read somewhere that you can change it in the boot options, much like an A1200, by holding the mouse buttons down, but I haven't done this yet.
Yep, CD32's have an Amiga Early Startup Menu exactly like the A1200's, where you can change between PAL and NTSC modes. Obviously you need a mouse connected to the CD32 to access it.
Steve.