MyClass.h

@interface MyClass : NSObject {
	@private
	BOOL myarray[32][24];

}
@end

MyClass.m

#import "MyClass.h"

@implementation MyClass

-(id) init
{
    if( (self=[super init] ))
    {

        // Initialise myarray.
        const int num_columns = sizeof(myarray)/sizeof(myarray[0]);
	const int num_rows = sizeof(myarray[0])/sizeof(myarray[0][0]);
	for (int x=0; x<num_columns; x++)
	{
            for (int y=0; y<num_rows; y++)
            {
                myarray[x][y] = ... ;
            }
	}

    }
    return self;
}

@end