C220 : fixed screen with a couple of parallax/exposure correction marks. Knob wind with fold out crank. Manual shutter cocking on all lenses. Single frame-mount shutter release, with cable release. Focus scale and parallax/exposure correction by plates on the left side of the bellows. Some variations without a cold flash shoe.
C330: interchangable screens with scale for parallax/exposure correction. Moving parallax/exposure indicator in the finder (remember to 'program' the focal length). Auto shutter cocking on most lenses. Crank advance and shutter cocking. Frame shutter release and 'chin' release. The 'chin' release has the cable release socket. Focus scale uses a revolving rod. Has a cold flash shoe.
If you really need details, http://www.btinternet.com/~g.a.patte...faq/m_faq.html and the photopages at http://www.btinternet.com/~g.a.patterson/
There are some cosmetic differences and the internal mechanisms have differences too.