How can I get a an array of parent
ABGroups for an
ABPerson in MonoTouch?
Sadly you cannot. The ABPersonCopyParentGroups API is only documented for OSX (web site and header files) and a bit of testing shows it is not available on iOS.
Presumably you do it the same way you do in Obj-C, using ABPersonCopyParentGroups.
See also: Find which ABPerson's group (ABGroup) in iOS4