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One little thing is puzzling me about creating an object from your own class. What is the difference between:

myClass *myObject;

and

myClass *myObject=[[myClass alloc] init];

The first line of code:

myClass *myObject;

only creates a variable that is a pointer to an object of type myClass.  In Objective-C (and C) prefixing a variable w/ an * specifies that the variable is a pointer.  However, nothing is assigned to the pointer.

In the second line of code:

myClass *myObject=[[myClass alloc] init];

an object of type MyClass has been created in memory and a pointer that points to the object's address in memory is assigned to myObject.

Don't forget that whenever you use alloc, you have to remember to call release/autorelease on the object when it's no longer being used.  For more details, look at Lecture 6 from the Stanford course: