4 phase PM type stepper

Hi,

Hoping for some answers for the hopefully not too irritating
questions:

MOTOR SPECIFICATIONS:
No. of phase : 4 phase PM Type (pulse modulation?)
Step angle : 7.5deg+-5%
voltage : 5
winding resis: 70 ohm
winding induc: 30mH (1Vrms 1kHz)
start pulse rate: 600pps
slew pulse rate: 610pps
holding torque : 180g-cm
no. of wires : 6
QUESTIONS:

What is the difference between 2 phase and 4 phase steppers?
Are 7.5 deg. steppers good enough for CNC work?
What is starting/slewing pulse rate? What significance does it have
for motor controller?
1g-cm = ??? oz-in (sorry, but someone on the list will be able to do
this conversion without having to hunt for conversion tables)
Will the motor be compatible with those CCED motor controllers
(gecko, camtronics, etc.)