Sorting NSArray of dictionaries by value of a key in the dictionaries

I think this will do it:

brandDescriptor = [[NSSortDescriptor alloc] initWithKey:@"brand" ascending:YES];
sortDescriptors = [NSArray arrayWithObject:brandDescriptor];
sortedArray = [myArray sortedArrayUsingDescriptors:sortDescriptors];

I pulled the code from Sort Descriptor Programming Topics. Also, Key-Value Coding comes into play, in that sortedArrayUsingDescriptors: will send a valueForKey: to each element in myArray, and then use standard comparators to sort the returned values.