MPhil at Cambridge = MA at most other (English) universities
There are not really any 'credits' attached to particular courses, etc. In Cambridge, at the end of the MPhil the History Faculty will provide you with a statement describing the workload, assessment structure, etc. that can be used as a transcript when applying for other things.
Some of the taught courses are indeed 11 months (October - August), such as the MPhil in Economic and Social History (if you want a course with a fairly large taught component I would recommend this one) and the MPhil in Medieval History. I have heard from some people here though that many of the 9 months MPhils may have to change to 11/12 months in the future (no idea when) to make them comparable.